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2018 (Gyo-Tsu) 153

2018.12.19
2018 (Gyo-Tsu) 153
Minshu Vol. 72, No. 6
Judgment concerning the constitutionality of the provisions of Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act, which specify the demarcation of constituencies for an election of members of the House of Representatives to be elected from single-seat constituencies
Case to seek invalidation of election
Judgment of the Grand Bench, dismissed
Tokyo High Court, Judgment of February 6, 2018
It cannot be said that the demarcation of constituencies for an election of members of the House of Representatives to be elected from single-seat constituencies provided by Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the general election of members of the House of Representatives held on October 22, 2017, and therefore said provisions cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution.

(There are opinions and dissenting opinions.)
Article 14, paragraph (1), Article 15, paragraphs (1) and (3), Article 43, paragraph (1), and Article 44 of the Constitution, Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act



Constitution

Article 14, paragraph (1)

(1) All of the people are equal under the law and there shall be no discrimination in political, economic or social relations because of race, creed, sex, social status or family origin.



Article 15, paragraphs (1) and (3)

(1) The people have the inalienable right to choose their public officials and to dismiss them.

(3) Universal adult suffrage is guaranteed with regard to the election of public officials.



Article 43, paragraph (1)

(1) Both Houses shall consist of elected members, representative of all the people.



Article 44

The qualifications of members of both Houses and their electors shall be fixed by law. However, there shall be no discrimination because of race, creed, sex, social status, family origin, education, property or income.





Public Offices Election Act

(Constituencies for Members of the House of Representatives)

Article 13, paragraph (1)

(1) Constituencies for members of the House of Representatives (to be elected from single-seat constituencies) are as provided in Appended Table 1, and one member is to be elected from each constituency.
The final appeal is dismissed.

The costs of the final appeal shall be borne by the appellants of final appeal.
Concerning reasons for a final appeal stated by the appellants of final appeal/appeal counsels for final appeal, YAMAGUCHI Kuniaki, KUNIBE Toru, and MISAO Michihiko, and the subagent for final appeal, NAGASHIMA Kenya

1. This case is a suit to seek invalidation of an election filed by the appellants who are voters in the respective constituencies in Tokyo 2nd, 5th, 8th, 9th and 18th Districts, and Kanagawa 15th District, with regard to the general election of members of the House of Representatives held on October 22, 2017 (hereinafter referred to as the "Election"), alleging, inter alia, that the provisions of the Public Offices Election Act concerning the demarcation of constituencies for elections of members of the House of Representatives to be elected from single-seat constituencies (hereinafter referred to as "elections in single-seat constituencies") are unconstitutional and invalid, and therefore that the elections held in the aforementioned constituencies as part of the Election pursuant to these provisions are also invalid.

2. The outline of the facts legally determined by the court of prior instance is as follows.

(1) The Public Offices Election Act, enacted in 1950, adopted the single-vote system based on medium-sized multi-seat constituencies as the election system for members of the House of Representatives. However, the Act for Partial Amendment to the Public Offices Election Act (Act No. 2 of 1994) was enacted in 1994, and through the subsequent partial amendments by Act No. 10 of 1994 and Act No. 104 of 1994, the combined election system of single-seat constituencies and proportional representation was introduced in place of the conventional single-vote system based on medium-sized multi-seat constituencies.

At the time when the Election was held, the number of members of the House of Representatives was 465, and 289 of which were to be elected from single-seat constituencies and 176 were to be elected by proportional representation (Article 4, paragraph (1) of the Public Offices Election Act). As for elections in single-seat constituencies, the entire area of the country was divided into 289 constituencies, and one member was to be elected from each of them (Article 13, paragraph (1) and Appended Table 1 of said Act; these provisions before and after the amendments discussed later are hereinafter referred to as the "provisions on demarcation"). As for elections of members to be elected by proportional representation (hereinafter referred to as "elections by proportional representation"), 11 constituencies were established nationwide, and the prescribed number of members was to be elected from each constituency (Article 13, paragraph (2) and Appended Table 2 of said Act). In a general election, elections in single-seat constituencies and elections by proportional representation are to be held concurrently, and each voter has one vote in each of the respective elections (Articles 31 and 36 of said Act).

(2) Under the Act for Establishment of the Council of Demarcation of Constituencies for Members of the House of Representatives (this Act before and after the amendments discussed later is hereinafter referred to as the "Act for Establishment of the Demarcation Council"), which was enacted concurrently with the aforementioned Act for Partial Amendment to the Public Offices Election Act in 1994, the Council of Demarcation of Constituencies for Members of the House of Representatives (hereinafter referred to as the "Demarcation Council") is to conduct investigation and deliberation on the revision of constituencies of members of the House of Representatives to be elected from single-seat constituencies, and when finding it necessary, the council is to draft a revision plan and recommend it to the Prime Minister (Article 2 of said Act).

With regard to the criteria for demarcation of constituencies pertaining to the aforementioned revision (these criteria before and after the amendments discussed later are hereinafter referred to as the "criteria for demarcation"), Article 3 of the Act for Establishment of the Demarcation Council after the amendment by Act No. 49 of 2016 (the amendment Act is hereinafter referred to as the "2016 Amendment Act," and the amended Act for Establishment of the Demarcation Council is hereinafter referred to as the "New Act for Establishment of the Demarcation Council") provides as follows: [i] paragraph (1) provides that the revision plan mentioned above is to be drafted with the aim of striking a balance among constituencies in terms of population (as used in said Article, it means the population of Japanese nationals based on the results of the recent population census), in accordance with the principle of ensuring that among the populations of constituencies the number calculated by dividing the largest population by the smallest population will not be two or more, and also be drafted in a reasonable manner by comprehensively taking into consideration the demarcation of administrative districts, geographical features, transportation conditions, and other circumstances; [ii] paragraph (2) provides that the number of constituencies to be established within the area of each prefecture is to be the number obtained by dividing the population of each prefecture by the standard divisor for single-seat constituencies (meaning a divisor where the sum of the numbers obtained by dividing the population of each prefecture by the divisor (any fractional part of less than one is to be rounded to the nearest integer above) coincides with the number of members of the House of Representatives to be elected from single-seat constituencies) (any fractional part of less than one in the calculation results is to be rounded to the nearest integer above) (the so-called Adams' method); and [iii] paragraph (3) provides that the number of constituencies for members of the House of Representatives to be elected from single-seat constituencies within the area of each prefecture is not to be changed when preparing a revision plan pertaining to the recommendation mentioned below under Article 4, paragraph (2) of said Act.

It is also provided that the Demarcation Council's recommendation on the revision of constituencies is to be made within one year from the day on which the population based on the results of the population census, which is conducted every 10 years pursuant to the provisions of the main clause of Article 5, paragraph (2) of the Statistics Act, is first made public in an official gazette (Article 4, paragraph (1) of the New Act for Establishment of the Demarcation Council). In addition, it is provided that, if, among the populations of Japanese nationals based on the results of the simplified population census conducted in constituencies in the fifth year from the aforementioned population census pursuant to the proviso to Article 5, paragraph (2) of the Statistics Act, the number calculated by dividing the largest population by the smallest population is two or higher, the aforementioned recommendation is to be made within one year from the day on which the population based on the results of the simplified population census in the fifth year is first made public in an official gazette (Article 4, paragraph (2) of the New Act for Establishment of the Demarcation Council).

Meanwhile, Article 3 of the Act for Establishment of the Demarcation Council prior to the amendment by Act No. 95 of 2012 (the amendment Act is hereinafter referred to as the "2012 Amendment Act," and Act for Establishment of the Demarcation Council prior to the amendment is hereinafter referred to as the "Former Act for Establishment of the Demarcation Council") provided as follows: [i] paragraph (1) provided that the revision plan mentioned above is to be drafted with the aim of striking a balance among constituencies in terms of population, in accordance with the principle of ensuring that among the populations of constituencies, the number calculated by dividing the largest population by the smallest population will not be two or more, and be drafted in a reasonable manner by comprehensively taking into consideration the demarcation of administrative districts, geographical features, transportation conditions, and other circumstances; and [ii] paragraph (2) provided that the number of constituencies to be established within the area of each prefecture is to be the sum of one apportioned to every prefecture (hereinafter referred to as the "rule of reserving one seat per prefecture"), plus the number calculated by deducting the number of prefectures from the number of seats for members of the House of Representatives to be elected from single-seat constituencies, and then apportioning the result to the prefectures in proportion to population (hereinafter these criteria for demarcation are referred to as the "former criteria for demarcation" and these provisions are referred to as the "former provisions on criteria for demarcation").

(3) The elections in single-seat constituencies, which formed part of the general election of members of the House of Representatives held on August 30, 2009 (hereinafter referred to as the "2009 Election"), were held based on the demarcation of constituencies as revised under the Act for Partial Amendment to the Public Offices Election Act (Act No. 95 of 2002) (hereinafter referred to as the "former demarcation of constituencies"). As of the day of the 2009 Election, the maximum disparity in the number of voters between constituencies was 2.304 to 1 (hereinafter all values indicating disparities are approximate figures), and the disparity with the constituency with the smallest number of voters was wider than 2 to 1 for 45 constituencies (Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act prior to the amendment by the 2012 Amendment Act, which specified the constituencies for members of the House of Representatives to be elected from single-seat constituencies in connection with the 2009 Election, are hereinafter collectively referred to as the "former provisions on demarcation").

The 2009 Election was addressed in 2010 (Gyo-Tsu) No. 207, the judgment of the Grand Bench of the Supreme Court of March 23, 2011, Minshu Vol. 65, No. 2, at 755 (hereinafter referred to as the "2011 Grand Bench Judgment"). With regard to Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council, which provided that a plan for revising constituencies should be drafted in accordance with the principle of ensuring that the maximum disparity in population between constituencies will be below 2 to 1, the 2011 Grand Bench Judgment evaluated this provision as specifying a reasonable criterion established with consideration given to equality in the value of votes. On the other hand, the same judgment pointed out that: by the time of the 2009 Election, the maximum disparity in the value of votes between constituencies had increased, and it was clear that the rule of reserving one seat per prefecture under paragraph (2) of said Article (apportioning at least one constituency to each prefecture) was the major factor causing such disparity; and, the rule of reserving one seat per prefecture, which had been introduced for the purpose of, inter alia, giving consideration to the sudden decrease in the number of seats in less populous regions, was no longer reasonable at the time of the 2009 Election in the same manner that it had been at the time of legislation. Accordingly, the 2011 Grand Bench Judgment held that the part of the former criteria for demarcation which pertains to the rule of reserving one seat per prefecture, and the former demarcation of constituencies under the former provisions on demarcation as revised according to said criteria, were in a state contrary to the constitutional requirement of equality in the value of votes at the time of the 2009 Election. Then, after stating that it cannot be said that the Diet had failed to make correction to such state within a reasonable period of time as required by the Constitution and therefore that the former provisions on criteria for demarcation and the former provisions on demarcation cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution, the same judgment held that in order to eliminate the aforementioned state within a reasonable period of time as required for correction due to the nature of the problems, legislative measures must be taken to meet the requirement of equality in the value of votes, such as abolishing, as quickly as possible, the rule of reserving one seat per prefecture, which is included in the former criteria for demarcation, and amending the former provisions on demarcation in line with the purport of Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council.

(4) In response to the 2011 Grand Bench Judgment, a bill for partial amendment to the Public Offices Election Act and the Act for Establishment of the Demarcation Council was enacted on November 16, 2012, as the 2012 Amendment Act, which proposed the deletion of Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council and the reapportionment of constituencies involving no increase in any prefecture and one decrease each in five prefectures (decreasing the number of constituencies by one in each of five prefectures with lower populations per member, without increasing the number of constituencies in any prefecture; the same applies hereinafter). As a result of said amendment, Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council became Article 3 of the Act for Establishment of the Demarcation Council as amended, and only the content of said Article newly became the criteria for demarcation.

The House of Representatives was dissolved on the day on which the 2012 Amendment Act was enacted, and as it was impossible due to time deficit to newly demarcate constituencies before the general election of members of the House of Representatives, which was held on December 16, 2012 (this election is hereinafter referred to as the "2012 Election"), the election was held based on the former demarcation of constituencies, as was the case with the 2009 Election.

The 2012 Election was addressed as follows in 2013 (Gyo-Tsu) No. 209, No. 210, and No. 211, the judgment of the Grand Bench of the Supreme Court of November 20, 2013, Minshu Vol. 67, No. 8, at 1503 (hereinafter referred to as the "2013 Grand Bench Judgment"): the former demarcation of constituencies under the former provisions on demarcation was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the 2012 Election as it had also been at the time of the 2009 Election; however, it cannot be said that the Diet had failed to make correction within a reasonable period of time as required by the Constitution, and therefore the former provisions on demarcation cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution. In the same judgment, the Grand Bench held that the Diet must continue to make constant efforts toward developing an election system in line with the purport of Article 3 of the Act for Establishment of the Demarcation Council as amended by the 2012 Amendment Act.

(5) Following the enactment of the 2012 Amendment Act, the Demarcation Council made a recommendation pursuant to the Supplementary Provisions of said Act. In response to this recommendation, on June 24, 2013, a bill for partial amendment to the 2012 Amendment Act was enacted as Act No. 68 of 2013 (hereinafter referred to as the "2013 Amendment Act"). It proposed to re-demarcate 42 constituencies in 17 prefectures in a manner that the disparity in population between constituencies would be below 2 to 1 based on the premise of the reapportionment of constituencies involving no increase in any prefecture and one decrease each in five prefectures.

Based on the demarcation of constituencies resulting from the aforementioned revision, and on the basis of the results of the population census conducted on October 1, 2010, the maximum disparity in population between constituencies was supposed to be 1.998 to 1. Meanwhile, as of the date of the general election of members of the House of Representatives held on December 14, 2014 (hereinafter referred to as the "2014 Election"), the maximum disparity in the number of voters between constituencies was 2.129 to 1, and the disparity with the constituency with the smallest number of voters exceeded 2 to 1 for 13 constituencies.

The 2014 Election was addressed as follows in 2015 (Gyo-Tsu) No. 253, the judgment of the Grand Bench of the Supreme Court of November 25, 2015, Minshu Vol. 69, No. 7, at 2035 (hereinafter referred to as the "2015 Grand Bench Judgment"): the number of seats apportioned under the former criteria for demarcation was not reviewed with regard to prefectures other than those subject to the reduction in the number of seats through the aforementioned reapportionment of constituencies involving no increase in any prefecture and one decrease each in five prefectures, and the major cause of such disparity in the value of votes is the inconsistency between the number of seats actually apportioned to many prefectures and the number of seats that should have been apportioned to them as a result of the reapportionment of seats according to the criteria for demarcation established after the deletion of Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council, which had provided for the rule of reserving one seat per prefecture; the emergence of such disparity in the value of votes should be described as the evidence of the fact that the development of an election system that is in its entirety in line with the purport of Article 3 of the Act for Establishment of the Demarcation Council as amended by the 2012 Amendment Act cannot be deemed to have been achieved; and it must be said that the demarcation of constituencies revised by the 2012 Amendment Act as amended by the 2013 Amendment Act was still in a state contrary to the constitutional requirement of equality in the value of votes. The court held that the Diet is deemed to be permitted to, as a realistic option that it may choose at its discretion, develop an election system in line with the purport of said Article by making gradual reforms, and when also taking into account that the Diet continued the reform process for the election system even after this re-demarcation among other factors, it cannot be said that the efforts that the Diet had made toward achieving correction from the time of the rendition of the 2011 Grand Bench Judgment until the time of the 2014 Election were not a reasonable exercise of the legislative discretion, and therefore it cannot be said that the Diet had failed to make correction within a reasonable period of time as required by the Constitution.

(6) Before and after the enactment of the 2013 Amendment Act, discussions had continued at the Diet for the review of the election system in an effort to ensure that the system would not be in a state contrary to the constitutional requirement of equality in the value of votes even when considering the population movements in the future, including the possibility of reducing the total number of seats. Based on a decision made by the House of Representatives Steering Committee on June 19, 2014, the Research Council on the Election System for the House of Representatives (hereinafter referred to as the "Election System Research Council") was set up within the House of Representatives as an advisory panel to the House of Representatives Speaker consisting of experts, in order to conduct research and study concerning the election system for the House of Representatives.

From September 2014, the Election System Research Council held meetings periodically, conducting research and study including hearing of opinions from each political party concerning such issues as an ideal election system for members of the House of Representatives, reduction in the number of seats, and correction of the disparity in the value of votes, and submitted a report on the election system for the House of Representatives to the House of Representatives Speaker on January 14, 2016.

The aforementioned report proposed the following: [i] with regard to an ideal election system for members of the House of Representatives, the current combined election system of single-seat constituencies and proportional representation should be maintained; and [ii] with regard to reduction in the number of seats, a possible approach would be to reduce the number of members of the House of Representatives by 10 to 465 (reducing the number of the members to be elected from single-seat constituencies by six to 289, and reducing the number of those to be elected by proportional representation by four to 176). In addition, [iii] with regard to the correction of the disparity in the value of votes, the report indicated that the method of apportionment of seats to each prefecture for elections in single-seat constituencies should satisfy the following requirements: the seats should be apportioned based on an apportionment method with proportionality; the disparity in the value of votes between prefectures should be minimized in order to keep the disparity in the value of votes between constituencies small; the number of seats apportioned to each prefecture should only change slightly; and the method should be capable of functioning effectively to a certain degree into the future. As a result of examinations in light of these requirements, the report proposed that seats should be apportioned to each prefecture by a method whereby the sum of the numbers obtained by dividing the population of each prefecture by a certain value (the divisor for single-seat constituencies) and rounding any fractional part to the nearest integer above coincides with the number of members to be elected from single-seat constituencies (Adams' method). The report also set forth that the apportionment of seats to each prefecture is to be reviewed on the basis of the population based on the results of the population census conducted every 10 years, from the standpoint of maintaining the stability of the system, and if, as a result of the simplified population census conducted five years later, the disparity in population between constituencies becomes 2 to 1 or higher for any constituencies, the Demarcation Council is to review the demarcation of the relevant constituencies to make the aforementioned disparity less than 2 to 1, without changing the apportionment of seats to each prefecture.

(7) In response to the aforementioned report of the Election System Research Council, the Act for Partial Amendment to the Act for Establishment of the Council of Demarcation of Constituencies for Members of the House of Representatives and the Public Offices Election Act (the "2016 Amendment Act") was enacted on May 20, 2016, including the revision to reduce the number of members of the House of Representatives by 10 from 475 to 465 (reduction of the number of the members to be elected from single-seat constituencies by six to 289, and reduction of the number of those to be elected by proportional representation by four to 176), and as mentioned in (2) above, the revision to adopt the Adams' method as the method of apportionment of seats to each prefecture. The 2016 Amendment Act provided that any change to the number of constituencies in each prefecture by the Adams' method is to be made based on the results of the population census conducted every 10 years, starting from 2020, from the standpoint of maintaining the stability of the system, and if, as a result of the simplified population census conducted five years later, the disparity in population of Japanese nationals (hereinafter simply referred to as the "population") between constituencies becomes 2 to 1 or higher for any constituencies, the demarcation of constituencies is to be revised to make said disparity less than 2 to 1, without changing the number of constituencies in each prefecture.

Meanwhile, as a measure for correcting the disparity in the value of votes until the number of constituencies in each prefecture is changed by using the Adams' method, the 2016 Amendment Act provided in its Supplementary Provisions that the Demarcation Council is to draft a revision plan and make a recommendation on demarcation of constituencies based on the results of the population census conducted in 2015 (hereinafter referred to as the "2015 population census"), on a premise to reduce the number of the members to be elected from single-seat constituencies by six. The 2016 Amendment Act also set forth that, in preparing the revision plan, from the standpoint of securing the stability of the election system by minimizing the number of prefectures that are affected by the reduction in the number of constituencies in each prefecture, the prefectures to be subject to the reduction are, among the prefectures for which the number of constituencies to be obtained by the Adams' method is smaller than the number of constituencies prior to the amendment, the six prefectures which are ranked last in terms of the number calculated by dividing the population of the prefecture based on the results of the 2015 population census by the number of constituencies obtained by the Adams' method, in ascending order, and provided that the number of constituencies prior to amendment is to be maintained for the other prefectures. In addition, the 2016 Amendment Act provided that constituencies are to be demarcated in accordance with the principle of ensuring that the disparity in population between constituencies based on the results of the 2015 population census will be less than 2 to 1 and that such disparity based on the population estimate for 2020, when the next population census will be conducted, will also be less than 2 to 1, with the aim of striking a balance among constituencies in terms of population based on the results of the 2015 population census and that in terms of the population estimate for 2020, in a reasonable manner by comprehensively taking into consideration the demarcation of administrative districts, geographical features, transportation conditions, and other circumstances.

Following the enactment of the 2016 Amendment Act, the Demarcation Council conducted deliberations, and on April 19, 2017, the Demarcation Council recommended a revision plan to the Prime Minister to re-demarcate 97 constituencies in 19 prefectures on the premise of reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures as mentioned above. Receiving said recommendation, the Cabinet submitted a bill for partial amendment to the 2016 Amendment Act to the Diet on May 16, 2017, as a legislative measure to specify, under the 2016 Amendment Act, the effective date of the provisions in said Act to amend the Public Offices Election Act in order to implement said reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures, and also to specify the matters to be amended in the Public Offices Election Act in order to revise the demarcation of constituencies based on said revision plan. On June 9, 2017, this amendment bill was enacted as Act No. 58 of 2017 (hereinafter referred to as the "2017 Amendment Act"). The provisions for amending the Public Offices Election Act that included the aforementioned reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures and the revision of the demarcation of constituencies based on this came into effect on July 16, 2017. In accordance with these provisions for amendment, seats were reapportioned while involving no increase in any prefecture and one decrease each in six prefectures, and constituencies were re-demarcated as specified in the aforementioned revision plan (hereinafter the provisions of Article 13, paragraph (1) and Appended Table 1 of the Public Offices Election Act after this amendment are referred to as the "Provisions on Demarcation," and the demarcation of constituencies after this revision based on the Provisions on Demarcation is referred to as the "Demarcation of Constituencies").

(8) The House of Representatives was dissolved on September 28, 2017, and the Election was held on October 22, 2017, based on the Demarcation of Constituencies. The Demarcation of Constituencies was intended to limit the maximum disparity in population between constituencies to 1.956 to 1 on the basis of the results of the 2015 population census, which was conducted on October 1, 2015. With regard to the disparity in the number of voters between constituencies as of the day of the Election, the disparity between the constituency with the largest number of voters (Tokyo 13th District) and the constituency with the smallest number of voters (Tottori 1st District) was 1.979 to 1, suggesting that no constituency accounted for a disparity of 2 to 1 or higher.

3 (1) It is understood that the Constitution of Japan requires equality in the substance of the right to vote, or in other words, equality in the value of votes. On the other hand, equality in the value of votes is not the absolute criterion for determining the design of an election system, but it must be realized in a harmonized manner in relation to other policy purposes and grounds that the Diet is duly authorized to consider. The Constitution provides that the number of seats, the constituencies, the method of voting and other matters concerning elections of members of the respective Houses of the Diet shall be specified by law (Article 43, paragraph (2), and Article 47), thus allowing the Diet to have broad discretion to determine the design of the election system.

We should say that in the case of adopting a system for holding an election of members of the House of Representatives by dividing the entire area of the country into a number of constituencies, the Constitution requires that securing equality in the number of voters or population per member to the greatest possible extent should be the most important and the essential criterion for determining the apportionment of seats and the demarcation of constituencies among the features of the design of an election system, but it is understood that the Constitution also allows the Diet to take other factors into consideration as long as it is reasonable to do so. When establishing specific constituencies, it is required that municipalities or other administrative districts created by subdividing prefectures be used as basic units, and while taking into account various factors including the size, population density, composition of residents, transportation conditions and geographical situations of the respective areas, efforts be made to ensure that the will of the people will be reflected properly in the process of carrying out national politics; and at the same time, to reconcile this with the requirement of securing equality in the value of votes. Consequently, determination as to the constitutionality of an election system is to be made by examining whether or not, even when all of these circumstances are comprehensively taken into account, the election system is justified as a reasonable exercise of the discretion vested in the Diet. Said features of the design of the election system specifically determined by the Diet should be judged to be unconstitutional only where these features run counter to said constitutional requirements, go beyond the bounds of the aforementioned discretion vested in the Diet even in consideration of such discretion, and are found unacceptable.

The reasoning presented above is in line with the purports of the series of Grand Bench Judgments previously handed down regarding elections of members of the House of Representatives, starting from 1974 (Gyo-Tsu) No. 75, the judgment of the Grand Bench of the Supreme Court of April 14, 1976, Minshu Vol. 30, No. 3, at 223 (see the aforementioned judgment of the Grand Bench of the Supreme Court of April 14, 1976; 1981 (Gyo-Tsu) No. 57, the judgment of the Grand Bench of the Supreme Court of November 7, 1983, Minshu Vol. 37, No. 9, at 1243; 1984 (Gyo-Tsu) No. 339, the judgment of the Grand Bench of the Supreme Court of July 17, 1985, Minshu Vol. 39, No. 5, at 1100; 1991 (Gyo-Tsu) No. 111, the judgment of the Grand Bench of the Supreme Court of January 20, 1993, Minshu Vol. 47, No. 1, at 67; 1999 (Gyo-Tsu) No. 7, the judgment of the Grand Bench of the Supreme Court of November 10, 1999, Minshu Vol. 53, No. 8, at 1441; 1999 (Gyo-Tsu) No. 35, the judgment of the Grand Bench of the Supreme Court of November 10, 1999, Minshu Vol. 53, No. 8, at 1704; 2006 (Gyo-Tsu) No. 176, the judgment of the Grand Bench of the Supreme Court of June 13, 2007, Minshu Vol. 61, No. 4, at 1617; the 2011 Grand Bench Judgment; the 2013 Grand Bench Judgment; and the 2015 Grand Bench Judgment), and there is no need to modify it.

(2) From the viewpoint explained above, we examine the constitutionality of the Provisions on Demarcation and the Demarcation of Constituencies at the time of the Election.

As mentioned in 2(6) and (7) above, the Election System Research Council, which was an advisory panel to the House of Representatives Speaker that was established before the 2014 Election, held repeated discussions on the election system for members of the House of Representatives. After the 2015 Grand Bench Judgment was handed down, the Election System Research Council submitted a report proposing reduction in the number of the members to be elected from single-seat constituencies by six and adoption of the Adams' method, which is one of the apportionment methods proportional to the population of each prefecture, as a new seat apportionment method for correcting the disparity in the value of votes, among other matters. The 2016 Amendment Act, which was enacted in response to this report, established provisions with the same content as the report, and provided that the apportionment of seats to each prefecture by the Adams' method is to be carried out based on the results of the population census conducted every 10 years, starting from 2020, and if the disparity in population between constituencies based on the simplified population census conducted five years later becomes 2 to 1 or higher for any constituencies, the demarcation of constituencies is to be revised to make said disparity less than 2 to 1.

Moreover, as a measure to be taken until the apportionment of seats is conducted by the Adams' method and with an aim to correct the disparity while securing the stability of the election system, the 2016 Amendment Act provided as follows in its Supplementary Provisions: the reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures is to be implemented, whereby the number of constituencies is to be reduced by one in each of the six prefectures in which the number of constituencies is expected to decrease if seats are apportioned by the Adams' method based on the results of the 2015 population census and which have the smallest population per member. In addition, the Supplementary Provisions set forth that constituencies are to be re-demarcated so as to make the disparity in population between constituencies less than 2 to 1 throughout the five years until 2020, when the next population census will be conducted, based on the same criteria for demarcation as that under Article 3, paragraph (1) of the New Act for Establishment of the Demarcation Council. On such basis, the 2017 Amendment Act, which was enacted based on the recommendation of a revision plan by the Demarcation Council, amended the Public Offices Election Act to revise the demarcation of constituencies for 97 constituencies in 19 prefectures, and the Election was conducted based on the Demarcation of Constituencies specified under the Provisions on Demarcation as amended.

As a result, the disparity in the value of votes between constituencies based on the Demarcation of Constituencies was reduced to 1.956 to 1 in terms of the maximum disparity in population based on the results of the 2015 population census, and to 1.979 to 1 in terms of the maximum disparity in the number of voters as of the day of the Election, leaving no constituency with the ratio of 2 to 1 or higher as compared with the constituency with the smallest number of voters.

In this manner, the amendment by the 2016 Amendment Act and the 2017 Amendment Act, including the amendment pertaining to the Provisions on Demarcation, aimed to reduce the maximum disparity in population between constituencies, etc. as mentioned above by first implementing a legislative measure to considerably reduce the disparity in the value of votes between constituencies through apportionment of seats to each prefecture by the Adams' method, which is a method proportional to population, in revising the demarcation of constituencies based on the results of the population census to be conducted in 2020, and to maintain such state in a stable manner, and then conducting reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures and revising the demarcation of constituencies as measures to correct the disparity until seats are apportioned by the Adams' method. The amendment can be evaluated as having achieved gradual correction from the viewpoint of ensuring the stability of the election system, while meeting the demand of securing equality in the value of votes.

Indeed, in the Election, there was no change in the numbers of seats that had been apportioned to the prefectures other than those in which the number of constituencies decreased due to the 2012 Amendment Act and the 2016 Amendment Act, based on the former criteria for demarcation, including the rule of reserving one seat per prefecture, and these prefectures include those to which a different number of seats will be apportioned if apportionment is conducted by the Adams' method. However, as mentioned in 2(4) through (7) above, due to the legislative measures under the 2012 Amendment Act to the 2017 Amendment Act, Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council was deleted, and successive revisions were made including review of apportionment of seats whereby the number of seats apportioned under the rule of reserving one seat per prefecture was decreased by one in each of the 11 prefectures which had the smallest population per member, and revision of the demarcation of constituencies to reduce the disparity in the value of votes between constituencies. As a result, the maximum disparity in the number of voters between constituencies as of the day of the Election narrowed as mentioned above. In addition, at the time the Election was conducted, a legislative measure was already implemented to start the apportionment of seats to each prefecture by the Adams' method based on the result of the population census conducted every 10 years, starting from 2020, thereby completely eliminating the effects of the apportionment of seats based on the rule of reserving one seat per prefecture. Considering the content of such legislative measure and the state of disparity that has narrowed as a result, it cannot be said that the Demarcation of Constituencies was in a state contrary to the constitutional requirement of equality in the value of votes based on the fact that, in the Election, there were prefectures for which the number of seats apportioned based on the former criteria for demarcation, including the rule of reserving one seat per prefecture, differed from the number of seats to be apportioned if seats were apportioned to each prefecture by the Adams' method.

By comprehensively taking the above circumstances into consideration, it can be said that the Provisions on Demarcation aimed to correct the disparity based on the purports of the 2011 Grand Bench Judgment and the subsequent Grand Bench Judgments holding that legislative measures must be taken to meet the requirement of equality in the value of votes, and that the provisions were established based on various factors which the Diet is authorized to consider, including the point of time when the new apportionment method should be reflected in the apportionment of the number of members, while making the equality in the value of votes the most important and essential criterion. Therefore, it can be said that development of an election system compliant with Article 3, paragraph (1) of the New Act for Establishment of the Demarcation Council had been realized at the time of the Election. If so, the revision of the demarcation of constituencies and other revisions by the 2016 Amendment Act and the 2017 Amendment Act should be considered a reasonable exercise of the discretion vested in the Diet, and the state contrary to the constitutional requirement of equality in the value of votes, which the 2015 Grand Bench Judgment indicated with regard to the demarcation of constituencies at the time of the 2014 Election, can be deemed to have been eliminated by the 2016 Amendment Act as amended by the 2017 Amendment Act.

(3) Consequently, it cannot be said that the Demarcation of Constituencies specified by the Provisions on Demarcation was in a state contrary to the constitutional requirement of equality in the value of votes at the time of the Election, and the Provisions on Demarcation cannot be held to be in violation of Article 14, paragraph (1) or other provisions of the Constitution.

The appeal counsels argue that the Election does not constitute an election conducted by the apportionment method proportional to population based on the principle of one person one vote guaranteed by the Constitution and is therefore invalid, but it is clear from the discussion above that this argument is groundless. In addition, it cannot be said that there are deficiencies or conflicts in the reasons given as the reasons for final appeal with regard to the judgment in prior instance, which indicated a framework for determination similar to that mentioned in 3(1) above and determined the constitutionality of the Demarcation of Constituencies.

4. For the reasons described above, we can affirm the determination by the court of prior instance that the Provisions on Demarcation cannot be found to have been in violation of the Constitution at the time of the Election. The arguments made by the appeal counsels are not acceptable.

Accordingly, the Court unanimously decides as set forth in the main text. There are dissenting opinions by Justice ONIMARU Kaoru and Justice YAMAMOTO Tsuneyuki, respectively, and also opinions by Justice HAYASHI Keiichi and Justice MIYAZAKI Yuko, respectively.

The opinion by Justice HAYASHI Keiichi is as follows.

As I will explain below, I am concerned about the maximum disparity in population between constituencies that still remains, which reaches "almost 2 to 1," and the medium- to long-term effects of this judgment. Therefore, I dissent from the majority opinion with regard to the determination that the Demarcation of Constituencies is constitutional. However, it can be evaluated that considerable progress, though gradual, can be observed in dissolving the unreasonable system and narrowing the disparity as a result of the correction efforts made by the Diet in response to the series of Grand Bench Judgments, so, in conclusion, I agree with the majority opinion that the Provisions on Demarcation are constitutional.

1. (1) The majority opinion is considered to have faithfully followed the framework for determination indicated in the series of Grand Bench Judgments concerning the principle of equality in the value of votes and the discretion vested in the Diet, but I cannot state that the result of the Election, in which a maximum disparity reaching "almost 2 to 1" still remains between constituencies, is constitutional. This is because, while the maximum disparity in the 2014 Election, which was held to be unconstitutional by the 2015 Grand Bench Judgment (though owing to the fact that the rule of reserving one seat per prefecture had not yet been eliminated), was 2.129 to 1, the maximum disparity in the Election was only 0.15 lower at 1.979 to 1, and declaring the Election to be constitutional in spite of that is simply difficult to understand from the viewpoint of equality in the value of votes.

(2) The framework for determination indicated in the series of Grand Bench Judgments determining the constitutionality of a national election in terms of equality in the value of votes is a framework to determine an election to be unconstitutional if the design of an election system goes beyond the bounds of the discretion vested in the Diet and is unacceptable in terms of the requirement of equality in the value of votes, and not a framework to make the determination based on the numerical value of disparity per se. In that sense, there may be an indication that focusing on the disparity of "almost 2 to 1" per se misses the point. However, as long as the constitutionality of an election system is generally determined in relation to the principle of equality in the value of votes, I think appropriate evaluation cannot be made by detaching the issue from the numerical value of disparity, which is an objective measurement of the value of votes (indeed, the majority opinion to the effect that the election in question was constitutional has been formed on the basis of the 2011 Grand Bench Judgment, which made the evaluation that Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council, which provided that constituencies should be demarcated so that the maximum disparity in population between constituencies would be below 2 to 1, in principle, was "a reasonable criterion established with due consideration given to equality in the value of votes"; therefore, the majority opinion is also considered to have in mind the numerical value, i.e. the fact that the maximum disparity in the Election was below 2 to 1, as a determining factor). In evaluating the numerical value, I find it to be against the common sense to regard that there is no inequality even where there is a disparity in the value of votes as wide as 2 to 1 between constituencies. In addition, I do not find significance in the difference level of approximately 0.1 above or below the maximum disparity of 2 to 1. A maximum disparity of 1.979 to 1, which is below 2 to 1 but "almost 2 to 1," may be better than over 2 to 1, but there is no theoretical grounds to determine that the numerical value per se (so-called "static" numerical value) is within the scope allowed by the principle of equality in the value of votes, that is, constitutional. If the maximum disparity is approximately 2 to 1 as in the case of the Demarcation of Constituencies, it would be possible to consider that the demarcation falls within the scope of the broad discretion of the Diet and is allowable unless it is apparently unreasonable. However, from my point of view, such idea comes down to premising that a disparity of approximately 2 to 1 falls within the allowable scope, and it must be said that the idea lacks theoretical grounds and disregards the principle of equality.

(3) Due to the above, I would have to conclude that, although considerable improvements were made toward reducing the disparity in the Election, the election system has some unreasonable aspect as long as it has still produced a large disparity of "almost 2 to 1," and I cannot conclude that the election system pertaining to the Election has grown out of the unconstitutional state, and is now constitutional, as indicated by the majority opinion.

(4) With regard to the relationship between the principle of equality in the value of votes and disparity, although there is the difference of whether the maximum disparity in the election is approximately 2 to 1 or approximately 3 to 1, I hereby cite the statements I made (2(1) and (2)) in my opinion in 2017 (Gyo-Tsu) No. 47, the judgment of the Grand Bench of the Supreme Court of September 27, 2017, Minshu Vol. 71, No. 7 at 1139, rendered in relation to the election of members of the House of Councillors held in 2016, as they basically apply also to the Election, in which members of the House of Representatives, who represent citizens, are elected. On such basis, I would also like to add that the principle of one person one vote not only means that each citizen can cast one vote, but is also akin to the principle of equality in the value of votes, which requires that the value of each vote must not be subject to discrimination based on one's attributes such as property or status, and that the prohibition of such discrimination, which includes discrimination based on the place of residence, should be strictly considered. In other words, other factors such as geographical, historical, and social factors, which may be considered by the Diet in building an election system, are subordinate to the principle of equality in the value of votes as long as they are not constitutional requirements per se, so unless there are exceptionally reasonable grounds, and unless the presence of such grounds is clearly explained, I consider that the equality in the value of votes must be preferentially respected.

(5) Meanwhile, from an international perspective, it is not easy to make simple comparisons between countries as they have different backgrounds, but the international trend is to aim toward equalizing the value of votes as much as possible. Thus, we can say that efforts should be directed toward reducing the disparity as much as possible, also from such viewpoint. While I have also mentioned this in the part cited above, in the case of the United Kingdom, which has provided a model for Japan's parliamentary government and which had also been considered as a model when Japan introduced the single-seat constituency system, the country has aimed to build a demarcation system restricting the disparity to within 5% in principle, which is equivalent to a maximum disparity of 1.1 to 1, by law amendment, and this would serve as a useful reference. Indeed, in the United Kingdom, [i] the total number of seats of the lower house, all of which are contested in single-seat constituencies, is 600 seats (as amended), which is more than double the total number of seats for members of Japan's House of Representatives to be elected from single-seat constituencies, and [ii] the 600 seats are, except for four seats exceptionally apportioned to islands, first apportioned to the four areas that constitute the United Kingdom, which are England, Scotland, Wales, and Northern Ireland, in proportion to their populations, and the approximately 500 seats apportioned to England are further apportioned to nine subordinate areas also in proportion to their populations. In other words, in simple terms, nearly 600 seats are apportioned to 12 apportionment bases, and each apportionment base has 18 to 81 constituencies, so disparity between constituencies can be adjusted quite flexibly. As the United Kingdom has such circumstances, there may be an opinion that the country's system would not serve as a useful reference for Japan, but conversely, it can also be considered that the system including such aspect flexibility would serve as a useful reference.

2 (1) Another reason concerning which I cannot totally agree with the majority opinion is that there is a concern about the medium- to long-term effects of this judgment. In other words, it is highly likely that rendering a determination that the Election is constitutional in this judgment would be taken as practically giving a comprehensive endorsement, so to speak, to the election system based on the 2016 Amendment Act and the 2017 Amendment Act. Furthermore, the effect of that determination may continue not only up to 2022, when the apportionment of seats by the Adams' method is expected to be actually conducted, but well over a period of about 15 years extending until after the subsequent population census (in other words, irrespective of the demographic status, the demarcation of constituencies in the elections for the House of Representatives would all be regarded as constitutional during that period). In fact, however, even if seats are apportioned by the Adams' method, [i] as long as the number of members is maintained or further reduced, and [ii] the current method of apportioning seats to each prefecture is maintained, it cannot be denied that there are limits to reducing the disparity even under the current conditions. Moreover, as depopulation in rural areas and congestion in urban areas, particularly in the Tokyo metropolitan area, are expected to progress further, it is considered that the realistic possibility is high for emergence of a structure where the maximum disparity of approximately 2 to 1 will become constant.

(2) In a situation where it was structurally difficult to hold down the maximum disparity to below 2 to 1, the criterion of below 2 to 1 might have been a reasonable target in the sense that it was important for the ratio to fall below 2 to 1. However, this does not mean that the ratio may be kept at approximately 2 to 1. In light of the importance of equality in the value of votes, it is not appropriate to regard "approximately 2 to 1" as the final goal. If a maximum disparity of as much as approximately 2 to 1 becomes constant, it will practically impair the equality in the value of votes. The fact that an apportionment method "proportional to population" creates a disparity as large as 2 to 1 should be considered to be paradoxical. If such situation is to occur even when seats are apportioned by the Adams' method, it would mean that the method is not functioning sufficiently as an apportionment method proportional to population, so it would be proper to review once again whether any structural problem that could be considered unconstitutional has occurred, as in the case of the rule of reserving one seat per prefecture. My concern is that this judgment could lead to a situation where such review would be regarded unnecessary.

3. In the past, Winston Churchill stated that "one vote, one value" was a principle concerning a representative democracy along with one person one vote. He indicated that there could only be an approximation to achieve the principle, and it could only arise out of the process of gradual improvement due to various reasons, but he proclaimed that all agreed "this process should be constant and active" (UK Parliament minutes of February 16, 1948). I consider that achieving equality in the value of votes indeed involves political difficulties and must be gradual, but as it is an important constitutional issue concerning the fundamental of a representative democracy, the results of this judgment would not be sufficient, and indeed "constant and active" efforts should be made toward improvement.

The opinion by Justice MIYAZAKI Yuko is as follows.

I agree with the conclusion of the majority opinion, but I consider that the Demarcation of Constituencies at the time of the Election was in a state contrary to the constitutional requirement of equality in the value of votes. As I do not fully agree with the underlying reasons of the majority opinion, including that point, I will state my reasons below.

1. With regard to apportionment of seats to constituencies and demarcation of constituencies in election of members of the House of Representatives, the aforementioned series of Grand Bench Judgments, starting from the judgment of the Grand Bench of the Supreme Court of April 14, 1976, indicated the following interpretation: the Constitution requires that securing equality in the number of voters or population per member to the greatest possible extent (i.e. proportionality to population) should be the most important and essential criterion, but the Constitution also allows the Diet to take other factors (i.e. factors other than proportionality to population) into consideration as long as it is reasonable to do so. In this manner, the constitutional requirement of equality in the value of votes makes proportionality to population the most important and essential criterion and allows factors other than proportionality to population to be taken into consideration as long as they are reasonable, so it should be construed that the Constitution requires the apportionment of seats to each prefecture and the demarcation of constituencies premised thereon to be also conducted based on reasonable criteria or consideration factors. Thus, it should be construed that the provisions of Article 3, paragraph (1) of the Former Act for Establishment of the Demarcation Council and Article 3, paragraph (1) of the New Act for Establishment of the Demarcation Council established by amending the former provision, which were determined to be reasonable by the 2011 Grand Bench Judgment, also require that apportionment of seats and demarcation of constituencies be conducted based on such reasonable consideration factors.

Further, according to this interpretation, the 2011 Grand Bench Judgment determined that, under the former criteria for demarcation, the reason for apportioning seats based on the rule of reserving one seat per prefecture, that is, the reasonableness of giving consideration to less populous prefectures in which the number of seats would suddenly and substantially decrease as a result of apportionment in proportion to population (hereinafter referred to as "consideration to less populous prefectures") ceased to exist, and therefore the part of the former criteria for demarcation pertaining to the rule of reserving one seat per prefecture was in a state contrary to the constitutional requirement of equality in the value of votes. Meanwhile, the 2015 Grand Bench Judgment held that the demarcation of constituencies in the 2014 Election was still in a state contrary to the constitutional requirement of equality in the value of votes due to the reason that it could not be regarded as having corrected the apportionment of seats conducted based on the rule of reserving one seat per prefecture. On the other hand, the 2015 Grand Bench Judgment did not hold that the demarcation is considered a reasonable exercise of the discretion vested in the Diet as long as the maximum disparity is below 2 to 1.

Accordingly, if apportionment of seats conducted by taking into consideration unreasonable factors cannot be evaluated to have been corrected in practice, it should not be possible to recognize that such apportionment of seats is not in a state contrary to the constitutional requirement of equality in the value of votes, even if the maximum disparity is below 2 to 1.

2. In light of 1. above, in order to determine the constitutionality of the Provisions on Demarcation applied to the Election, it is considered necessary to first strictly examine whether or not the apportionment of seats conducted by taking into consideration unreasonable factors, which was found to be in a state contrary to the constitutional requirement of equality in the value of votes by the 2011 Grand Bench Judgment and further by the 2015 Grand Bench Judgment, was subsequently corrected under the Provisions on Demarcation. Therefore, I will examine this point.

(1) The Demarcation of Constituencies is the demarcation of constituencies specified in Appended Table 1 of the Public Offices Election Act as amended by the 2017 Amendment Act legislated by the Diet as the "legislative measure" set forth in Article 2, paragraph (5) of the Supplementary Provisions of the 2016 Amendment Act (hereinafter simply referred to as the "Supplementary Provisions") in response to a recommendation made by the Demarcation Council in the "Revision Plan Based on the Results of the Population Census Conducted in 2015" prepared based on paragraph (1) of said Article. This "Revision Plan Based on the Results of the Population Census Conducted in 2015" was prepared in accordance with the criteria specified in paragraphs (2) and (3) of said Article (hereinafter referred to as the "criteria under the Supplementary Provisions"), and the contents of the criteria under the Supplementary Provisions, unlike the contents of the criteria specified in Article 3 of the New Act for Establishment of the Demarcation Council (hereinafter referred to as the "criteria under the Main Provisions"), do not adopt the criterion of proportionality to population in the apportionment of seats to prefectures.

(2) Next, when we look at the contents of the criteria under the Supplementary Provisions, Article 2, paragraph (2) of the Supplementary Provisions separately provides for the apportionment criteria for the six prefectures that were made subject to reduction in the number of seats under the 2016 Amendment Act and the apportionment criteria for the other prefectures (hereinafter referred to as the "item (ii) areas"), and the respective apportionment criteria differ from each other. With regard to the prefectures included in the item (ii) areas, item (ii) of said paragraph provides that the "number of single-seat constituencies prior to amendment," that is, the number of single-seat constituencies specified in Appended Table 1 of the former provisions on demarcation is to be used as-is as the number of single-seat constituencies in the prefecture. Therefore, there is a question of how much of the effect of having taken into account the unreasonable factor of giving consideration to less populous prefectures remains in the Demarcation of Constituencies, as the demarcation includes the number of single-seat constituencies prior to amendment that has resulted from apportionment of seats under the former criteria for demarcation including the rule of reserving one seat per prefecture.

A. In considering what the "effect of having taken into account the unreasonable factor of giving consideration to less populous prefectures" is as a premise for examining this question, the rule of reserving one seat per prefecture, in the first place, is a technique to apportion larger numbers of seats to relatively less populous prefectures as compared to those apportioned under a method proportional to population, and to apportion smaller numbers of seats to populous prefectures as compared to those apportioned under a method proportional to population, and its major characteristic is to conduct "apportionment of a larger number of seats to less populous prefectures" and "apportionment of a smaller number of seats to populous prefectures" in an integrated manner. The previous Grand Bench Judgments have tended to rather focus on the unreasonableness of apportionment of seats to less populous prefectures, but as long as the factor of giving consideration to less populous prefectures is unreasonable, a practice of reducing apportionment to populous prefectures in order to apportion a larger numbers of seats to less populous prefectures is also unreasonable. We have to say that the distortion in apportionment generated as a result of apportioning seats under the former criteria for demarcation, which was conducted by taking into account unreasonable factors due to adoption of the rule of reserving one seat per prefecture, extends not only to less populous prefectures, but also to populous prefectures concurrently and inevitably.

B. As the distortion of apportionment caused by the rule of reserving one seat per prefecture must have definitely occurred both in relatively less populous prefectures and relatively populous prefectures, I will look at how and how much such distortion has been corrected. The amendments in the number of seats made after the 2011 Grand Bench Judgment, namely, the reapportionment of constituencies involving no increase in any prefecture and one decrease each in five prefectures by the 2012 Amendment Act and the reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures by the 2016 Amendment Act, both only conducted "reduction in the number of seats," which had an effect of taking away a seat that had been given under the rule of reserving one seat per prefecture by decreasing the number of seats by one in each less populous prefecture. In contrast, no amendment has been made to increase the number of seats in populous prefectures by law amendments after the 2011 Grand Bench Judgment.

C. The majority opinion mentioned the implementation of the "review of apportionment of seats to decrease the number of seats, which had been apportioned under the rule of reserving one seat per prefecture, by one in each of the 11 prefectures that had the smallest population per member" as one of the reasons for which the Provisions on Demarcation is not found to be in a state contrary to the constitutional requirement of equality in the value of votes. However, as mentioned in B. above, this review was not an amendment to review the number of seats apportioned to populous prefectures. In a precise sense, from the viewpoint of the ratio of the number of seats apportioned to each prefecture to the total number of single-seat constituencies, a reduction in the number of seats will decrease the denominator, which is the total number of single-seat constituencies, so even if the numerator (the number of seats apportioned to each prefecture) stays the same, it will have an effect of slightly increasing the ratio of the number of seats apportioned to populous prefectures to the total number of single-seat constituencies. However, the number of seats apportioned to the least populous prefecture (Tottori Prefecture) was neither revised by the reapportionment of constituencies involving no increase in any prefecture and one decrease each in five prefectures nor by the reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures, so these amendments to the number of seats had an extremely limited effect on the maximum disparity between constituencies. In addition, the majority opinion also mentioned the implementation of the review (revision) of the demarcation of constituencies for reducing the disparity in the value of votes between constituencies upon establishment of the Provisions on Demarcation as one of the reasons for which the Demarcation of Constituencies is found to be constitutional. However, populous prefectures were only made subject to the review within the extent that the maximum disparity between constituencies would not be 2 to 1 or higher, so the review does not have the meaning of correcting the apportionment of seats under the former criteria for demarcation, which was conducted by taking into account unreasonable factors due to adoption of the rule of reserving one seat per prefecture.

D. Looking at the results calculated on the basis of the population based on the 2015 population census, the disparity between constituencies in populous prefectures and the constituency with the smallest population per member has remained high (for example, looking at the disparity between each constituency and the least populous constituency prior to the revision by the Provisions on Demarcation, the disparity was 2 to 1 or higher for a total of 32 constituencies, among which 31 constituencies were those of prefectures with population size in the top 10). In addition, when comparing the disparity of population per member between prefectures with population size in the top five and the least populous prefecture and that between prefectures with population size in the bottom five and the least populous prefecture, the former is 1.717 to 1 at average and the latter is 1.2328 to 1 at average, showing a large gap between the two of approximately 0.5. Moreover, the calculation results based on the number of voters at the time of the Election also show that four constituencies indicating high disparity with the least populous constituency of almost 2 to 1 (ranging from 1.979 to 1 to 1.972 to 1) are all constituencies in Tokyo Prefecture with the top population size, and most of the constituencies with disparity in the top 60 are constituencies in prefectures with population size in the top 10. All of these phenomena have occurred because the numbers of seats that were apportioned to populous prefectures as a result of apportioning seats by taking into account the unreasonable factor of giving consideration to less populous prefectures have not been reviewed, and they indicate that the values of votes of voters in populous prefectures have been distorted to be lower as compared to the case of taking only reasonable factors into account.

E. When making calculation on the basis of population based on the 2015 population census, the maximum disparity in population per member between prefectures under the Provisions on Demarcation is 1.844 to 1 (between Tokyo Prefecture and Tottori Prefecture). This numerical value indicates that, although Tokyo Prefecture has a population approximately 23 times that of Tottori Prefecture, which has the smallest population, the number of seats apportioned to Tokyo Prefecture is 25 and that apportioned to Tottori Prefecture is 2 under the Provisions on Demarcation (both prefectures are item (ii) areas, so these numbers of seats are the numbers of members to be elected from single-seat constituencies that were specified prior to amendment by Article 2, paragraph (2), item (ii) of the Supplementary Provisions), and the number of seats apportioned to Tokyo Prefecture under the Provisions on Demarcation is only 12.5 times that of seats apportioned to Tottori Prefecture. However, if seats are apportioned to prefectures by the Adams' method, which is one of the methods proportional to population, on the basis of the results of the 2015 population census, the number of seats to be apportioned to Tokyo Prefecture will increase by three from 25 specified under the Provisions on Demarcation to 28 (if another method proportional to population, the largest remainder method with the Hare quota, is used, the number to be apportioned will increase by five to 30), and if these three incremental seats are apportioned to Tokyo Prefecture, the above disparity in population per member between Tokyo Prefecture and Tottori Prefecture will narrow from 1.844 to 1 to 1.646 to 1, improving by 0.198.

The disparity correction value (0.198) in the case where the number apportioned to Tokyo Prefecture (25) is corrected to 28 as mentioned above is as much as 32% higher than 0.15, which is the difference between 2.129 to 1 - the maximum disparity between constituencies at the time of the 2014 Election, which was determined to be unconstitutional by the 2015 Grand Bench Judgment - and 1.979 to 1 - the maximum disparity at the time of the Election. In other words, the difference in the maximum disparities caused by taking into account unreasonable factors (0.198) is larger than the difference between the maximum disparity in a state that was found to be unconstitutional by the 2015 Grand Bench Judgment and the maximum disparity in a state that was found to be constitutional by the majority opinion in this suit (0.15). This indicates that the disparity that has been caused as a result of taking into account the unreasonable factor of giving consideration to less populous prefectures in apportioning seats based on the former criteria for demarcation and that still remains the case without being corrected (this disparity can be regarded to be "embedded" in the numerical value of the maximum disparity between constituencies) is by no means small, and that it is a non-negligible level. In addition, the total number of citizens whose value of votes has been kept low due to the failure to correct the number of seats (specifically, the voters residing in populous prefectures) is by no means small (the total population of Tokyo, Kanagawa, Aichi, and Saitama Prefectures for which the number of seats will need to be increased if seats are apportioned to prefectures by the Adams' method on the basis of the population based on the 2015 population census accounts for nearly 30% of Japan's total population).

F. Moreover, if, in order to examine how much effect of having taken into account the unreasonable factor of giving consideration to less populous prefectures upon apportioning seats remains in the Demarcation of Constituencies, we focus on the fact that the maximum disparity in population between constituencies based on the results of the 2015 population census under the Demarcation of Constituencies was calculated as 1.956 to 1, and break down this disparity by factors that have caused such disparity, though merely as a conceptual exercise, and we can find the following.

(A) The Provisions on Demarcation adopt a method of first apportioning seats to prefectures (Step 1) and then conducting specific demarcation of constituencies in each prefecture based on it (Step 2). In light of this method, the following can be considered with regard to the maximum disparity in population between constituencies based on the results of the 2015 population census, which was 1.956 to 1: [i] the portion exceeding 1 and up to 1.844 (the maximum disparity in population per member between prefectures under the Provisions on Demarcation) (i.e. the portion equivalent to 0.844) is a disparity caused by Step 1, that is, the method of apportionment of seats to a prefecture that had been adopted by the Provisions on Demarcation (Article 2, paragraph (2), items (i) and (ii) of the Supplementary Provisions); and [ii] the portion exceeding 1.844 and up to 1.956 (i.e. the portion equivalent to 0.112) is a disparity caused by Step 2, that is, the specific demarcation conducted by each prefecture by taking into account the factors specified in paragraph (3) of said Article (including the demarcation of administrative districts, geographical features, transportation conditions, and other circumstances specified in item (ii) of said paragraph).

(B) Meanwhile, if seats are apportioned to prefectures by the Adams' method, which is one of the methods proportional to population, on the basis of the results of the 2015 population census, the maximum disparity between prefectures under the Provisions on Demarcation will narrow from 1.844 to 1 to 1.655 to 1, according to calculation. If so, it is obvious that this 1.655 to 1 is a disparity caused by apportioning seats to each prefecture by only taking into account the factor of proportionality to population (by the Adams' method). Therefore, the difference, that is, the portion of disparity exceeding 1.655 up to 1.844 (i.e. the portion equivalent to 0.189) can be considered to be "embedded" in 1.844 as a disparity caused as a result because the apportionment of seats, which served as a premise of the Demarcation of Constituencies, was conducted by taking into account a factor other than proportionality to population, that is, the unreasonable factor of giving consideration to less populous prefectures.

(C) If we break down the ratio of 1.956 to 1, which was the maximum disparity in population between constituencies based on the results of the 2015 population census under the Demarcation of Constituencies, by factors that have caused such disparity as mentioned above, the composition rates of the portion of the maximum disparity 1.956 which exceeds 1 (by 0.956) will be as follows: a. the portion of disparity caused as a result of apportioning seats to prefectures by a method proportional to population (0.655) accounts for approximately 68.5%; b. the "embedded" portion of disparity caused by the unreasonable factor of giving consideration to less populous prefectures as mentioned in (B) above (0.189) accounts for approximately 19.8%; and c. the portion of disparity caused by factors specified in Article 2, paragraph (3) of the Supplementary Provisions as mentioned in (A)[ii] above of which reasonableness has not been questioned in particular (0.112) accounts for approximately 11.7%. In other words, we can see that the portion of disparity caused as a result of apportioning seats while taking into account the unreasonable factor of giving consideration to less populous prefectures (b. above) is approximately 1.69 larger than the portion of disparity caused by the factors that were taken into account in the specific demarcation of constituencies (c. above).

(D) Incidentally, the effect against equality in the value of votes which is caused as a result of Japan's adoption of a method of first apportioning seats to prefectures is quite large even if the Adams' method, which is one of the methods proportional to population, is adopted (i.e. the 0.655 portion indicated in (C) above), but the fact that the portion of disparity caused by unreasonable factors is smaller than that does not justify the situation where any disparity caused by any of those unreasonable factors still remains. Rather, the fact that the percentage of the portion of disparity caused as a result of apportioning seats to prefectures by a method proportional to population is as large as this further enhances the importance of preventing the disparity caused by any unreasonable factor, in order to secure equality in the value of votes whose main idea is to reduce the disparity so as to approach 1 as closely as possible.

(3) A. Meanwhile, the majority opinion has mentioned the fact that the maximum disparity between constituencies based on the number of voters as of the day of the Election decreased to 1.979 to 1 as one of the reasons for which the Demarcation of Constituencies specified by the Provisions on Demarcation cannot be regarded to be in a state contrary to the constitutional requirement of equality in the value of votes. However, as the examination result in (2) above indicates, the decrease of the maximum disparity to 1.979 to 1 does not mean that the apportionment of seats that has taken into account unreasonable factors has been completely resolved and corrected. This is because, as in the case of the Provisions on Demarcation, even if the numbers of seats apportioned to the prefectures that belong to the item (ii) areas are not corrected but the maximum disparity between constituencies could be narrowed by conducting demarcation in such a manner to even out the population per constituency in a prefecture as much as possible (by, for example, dividing municipalities), the portion of disparity caused as an effect of apportioning seats by taking into account the unreasonable factor "embedded" therein will not disappear.

B. In addition, if, as a result of study, the apportionment of seats conducted by taking into account unreasonable factors cannot be evaluated as having been corrected substantially, it should not be possible to recognize that the apportionment of seats is not in a state contrary to the constitutional requirement of equality in the value of votes even where the maximum disparity is below 2 to 1. This is because, while the constitutional requirement of equality in the value of votes makes proportionality to population the most important and essential criterion and allows factors other than proportionality to population to be taken into consideration as long as they are reasonable, as mentioned in 1. above, an act of finding apportionment of seats that violates this requirement to be a reasonable exercise of the discretion vested in the Diet results in a preposterous outcome of subordinating the constitutional requirement to the discretion vested in the Diet. In the same way, as only reasonable factors are required to be reconciled with the requirement of securing equality in the value of votes in apportionment of seats or demarcation of constituencies, there is no reason to reconcile unreasonable factors with the requirement of securing equality in the value of votes.

C. In determining whether or not the Demarcation of Constituencies was in a state contrary to the constitutional requirement of equality in the value of votes, the majority opinion adopted a method to even take into account legislative measures that had yet to be reflected in the Provisions on Demarcation (in particular, Article 3, paragraphs (1) and (2) of the New Act for Establishment of the Demarcation Council as amended by the 2016 Amendment Act, i.e. the criteria under the Main Provisions mentioned in (1) above), and indicated "it cannot be said that the Demarcation of Constituencies was in a state contrary to the constitutional requirement of equality in the value of votes based on the fact that, in the Election, there were prefectures for which the number of seats apportioned based on the former criteria for demarcation, including the rule of reserving one seat per prefecture, differed from the number of seats to be apportioned if seats were apportioned to each prefecture by the Adams' method," but I do not agree with such determination method.

This is because, the issue of constitutionality of an election system (apportionment of seats and the demarcation of constituencies) from the viewpoint of equality in the value of votes is closely connected to the issue of how the Diet should exercise the discretion vested therein by the Constitution in legislating the election system, while at the same time, it is also an issue of "quality" of citizens' rights, that is, whether or not the rights to vote as specific rights exercised by citizens at the point of time of an election were compliant with the constitutional requirement of equality in the value of votes in that election. From the former viewpoint, there may be cases where it is appropriate to make the ultimate determination on constitutionality by also taking into account the contents of legislative measures that are yet to be reflected in the Provisions on Demarcation, and even making dynamic evaluation based on observation predicated on a time axis, as mentioned in 3(1) below. However, from the latter viewpoint, considering that citizens can exercise and enjoy the rights to vote for election of members of the House of Representatives only at the time of specific elections, and that provisions of law are only pie in the sky for citizens who actually exercise the rights to vote unless they are applied to actual elections, I think determination should be made focusing on whether the realities of specific rights to vote under the provisions on apportionment of seats and demarcation of constituencies that were applied at the point of time of an actual election (in the case of the Election, the Provisions on Demarcation correspond to such provisions) were in a state compliant with the constitutional requirement of equality in the value of votes. In that determination, the presence of any law that had yet to be applied to the actually applied demarcation of constituencies (in the case of the Election, Article 3, paragraphs (1) and (2) of the New Act for Establishment of the Demarcation Council correspond to such law) should not be taken into account.

In my view, if a disparity in the value of votes caused by taking into account unreasonable factors is found to have substantially occurred between prefectures to which seats were apportioned based on the former criteria for demarcation, the fact that "there were prefectures for which the number of seats apportioned based on the former criteria for demarcation, including the rule of reserving one seat per prefecture, differed from the number of seats to be apportioned if seats were apportioned to each prefecture by the Adams' method" should be regarded as indicating that the Demarcation of Constituencies applied at the point of time of the Election was in a state contrary to the constitutional requirement of equality in the value of votes.

(4) According to the results of the study in (2) above, it must be evaluated that, at the time of the Election, the Provisions on Demarcation had not corrected the apportionment of seats conducted by taking into account a factor that was determined to be unreasonable by the 2011 Grand Bench Judgment and had not eliminated its effects, and that the degree of the effects that still remained was a non-negligible level. As a result of taking into account this evaluation as well as the matters stated in (3) above, I consider that the Demarcation of Constituencies at the time of the Election was in a state contrary to the constitutional requirement of equality in the value of votes, that is, unconstitutional.

3. (1) However, the series of Grand Bench Judgments which have determined the constitutionality of elections of members of the House of Representatives have adopted a framework for determination whereby, even in the case where the apportionment of seats or demarcation of constituencies in a specific election subject to the suit was determined to be in a state contrary to the constitutional requirement of equality in the value of votes in terms of disparity in the value of votes, the court would determine that the provisions on apportionment of seats or provisions on demarcation violate provisions of the Constitution only if the Diet is judged to have failed to make correction within a reasonable period of time as required under the Constitution. Moreover, the 2013 Grand Bench Judgment and the 2015 Grand Bench Judgment held that it is allowable for the reform of the election system to be conducted gradually. Given these matters, in this case, it is considered significant, at least in this suit, to adopt the framework for determination whereby regarding the constitutionality of the law amendments and efforts made by the Diet for realizing correction of disparity based on the purport of the 2011 Grand Bench Judgment after the day on which the 2011 Grand Bench Judgment was handed down, particularly after the 2014 Election that was made subject to determination in the 2015 Grand Bench Judgment, determination is made not based on observation at the point of time of the Election, but instead based on dynamic observation predicated on a time axis, as a way to examine the constitutionality of apportionment of seats or demarcation of constituencies under the current Constitution.

(2) Thus, I will further conduct the aforementioned observation predicated on a time axis, and examine whether it can be said that the Diet failed to make correction within a reasonable period of time as required under the Constitution. In Article 3, paragraphs (1) and (2) of the New Act for Establishment of the Demarcation Council as amended by the 2016 Amendment Act that was established against the background indicated in the majority opinion, the apportionment criteria including adoption of the Adams' method, which is one of the methods proportional to population, (the criteria under the Main Provisions) were stipulated with regard to apportionment of seats to prefectures, and the contents of the criteria can be evaluated as aiming to achieve correction of disparity based on the purports of the series of Grand Bench Judgments, starting from the 2011 Grand Bench Judgment. In addition, the apportionment criteria stipulated in said Article (the criteria under the Main Provisions) are not found to include contents that can immediately be considered as unreasonable factors per se. Therefore, although the issue of when and how a revision plan to be drafted based on said Article will actually be recommended and when and how that revision plan will be legislated will remain in the future, these efforts can basically be evaluated positively at present.

(3) Meanwhile, the time axis of taking approximately six years from the day on which the 2011 Grand Bench Judgment was handed down until the establishment of the 2016 Amendment Act and the 2017 Amendment Act, and taking at least 10 years from the day on which the 2011 Grand Bench Judgment was handed down until the effect of the rule of reserving one seat per prefecture was actually eliminated (i.e. until the measure to legislate the demarcation of constituencies based on the criteria set forth in Article 3, paragraphs (1) and (2) of the New Act for Establishment of the Demarcation Council is taken) could be considered to be quite long, and it may be longer than the period which the general public would normally assume from the expression "reasonable period." However, taking into account that the achievement of the work for correction conducted by the Diet to date can be positively evaluated at present as mentioned above, it will be too much to say that the efforts toward realizing correction made by the Diet until the Election were not a reasonable exercise of legislative discretion. Accordingly, as a result of undergoing consideration based on the framework for determination indicated by the Grand Bench Judgments previously handed down with regard to determination of constitutionality of the demarcation of constituencies, I also think that the Provisions on Demarcation cannot be found to be in violation of Article 14, paragraph (1) or other provisions of the Constitution in this case.

4. Lastly, as a supplement to the reasons I have stated above, I would like to state the idea underlying this opinion for confirmation.

Considering that members of the House of Representatives are representatives of the people, and not representatives of regions such as prefectures, and the House of Representatives has a dissolution system under Japan's current Constitution, elections of members of the House of Representatives should always be conducted in a form in which the will of the people can be reflected properly as much as possible. The constitutional requirement of equality in the value of votes should be rationally guaranteed under the election system in order to justify that the election results reflect the will of the people. Including this point, there is no room for doubt that the equality in the value of votes is the most important and essential constitutional requirement, but it cannot be considered that the equality in the value of votes requires the degree of influence of each vote on the election results to be completely equal numerically, as indicated by the aforementioned judgment of the Grand Bench of the Supreme Court of April 14, 1976.

The election system of a representative democracy does not have a fixed and unchangeable form, but instead can take various forms. Yet, it is construed that, whatever the form, a specific election system which should be legislated by the Diet according to the Constitution must be one that enables a fair election (in the case of adopting the constituency system, including the sense that the system ensures a mechanism whereby voters can vote after being given the opportunity to learn about the specific candidates in respective constituencies in which the voters belong), and thereby realizes fair and effective representation. If so, given the restriction that it is impossible to accurately predict in advance dynamic changes in population (or the number of voters), which is a factor that has a substantial effect on apportionment of seats and demarcation of constituencies, even if legislation of election-related matters (apportionment of seats and demarcation of constituencies) by the Diet took into account certain non-population factors (such as demarcation of administrative districts) within the extent deemed reasonably necessary, while making equality in the value of votes the most important and essential criterion, as long as the election system legislated as a result achieves the objective of realizing fair and effective representation through a fair election, it should be possible to recognize such system as one form of election system of a representative democracy adopted under the current Constitution.

With regard to the single-seat constituency system portion of the current election system, law amendments should be made based on more in-depth discussions and empirical studies concerning ideal apportionment of seats and demarcation of constituencies, the frequency of change of the demarcation of constituencies (conversely, the stability of the demarcation of constituencies), and the point of balance with the constitutional requirement of equality in the value of votes, including whether to adopt deviation, which has been adopted in advanced countries as a measurement concerning equality in the value of votes, and whether it is appropriate to adopt a method whereby seats are apportioned not to prefectures but rather to regional blocs that are fewer in number than prefectures and that have smaller population differences by using a method proportional to population (since apportionment of seats to prefectures could cause a considerably large disparity, even by using a method proportional to population, as can be seen from the study in 2(2)F.(C) above), while also taking into account the dynamic changes in Japan's population and their trends. It is strongly hoped that continued efforts will be made to realize the single-seat constituency system in a manner that will further reduce the disparity or deviation, through such law amendments, so that the equality in the value of votes required by the Constitution will not fall behind the dynamic changes in population. However, whatever type of election system may be chosen, I think it will not be allowed under the current Constitution for an election system to cause a disparity in the value of the right to vote held by each voter due to unreasonable grounds. We should once again contemplate the fact that the ruling by the 2011 Grand Bench Judgment to the effect that apportioning more seats to relatively less populous prefectures was no longer reasonable was rendered on the basis that members of the House of Representatives are representatives of all the people, and that the dissolution system of the House of Representatives has a meaning of consulting the will of the people through an election.

The dissenting opinion by Justice ONIMARU Kaoru is as follows.

1. Dissenting from the majority opinion, I consider the Provisions on Demarcation at the time of the Election to have been unconstitutional and that it is reasonable to declare the Election to be illegal.

2. The Constitution provides that all of the people are equal under the law in Article 14, paragraph (1), and requires equality in rights to vote and equality in the substance of the right to vote, that is, the value of the vote of each voter in Article 15, paragraphs (1) and (3) and the proviso to Article 44. An election system under a representative democracy aims to gather the opinions of voters through elected representatives, and properly reflect them in assemblies, etc. Therefore, the results of an election that was conducted in a state where there is a disparity in the value of votes that is not found to be reasonable cannot be considered to properly reflect the opinions of voters, and it is difficult to regard such election as a duly conducted election as referred to in the Preamble of the Constitution.

With regard to cases seeking invalidation of elections of members of the House of Representatives due to inequality in the value of votes or other reasons, the majority opinions in the series of Grand Bench Judgments that have been handed down since April 14, 1976, have also basically indicated the aforementioned idea that the equality in the value of votes is a constitutional requirement (the aforementioned judgment of the Grand Bench of the Supreme Court of April 14, 1976, the 2015 Grand Bench Judgment, etc.). Similarly, the majority opinion in this judgment also simply points out "It is understood that the Constitution of Japan requires equality in the substance of the right to vote, or in other words, equality in the value of votes."

3. At the same time, the majority opinion stated as follows regarding the fact that the maximum disparity in the number of voters between single-seat constituencies as of the day of the Election was below 2 to 1, but almost 2 to 1: "equality in the value of votes is not the absolute criterion for determining the design of an election system, but it must be realized in a harmonized manner in relation to other policy purposes and grounds that the Diet is duly authorized to consider. The Constitution provides that the number of seats, the constituencies, the method of voting and other matters concerning elections of members of the respective Houses of the Diet shall be specified by law (Article 43, paragraph (2), and Article 47), thus allowing the Diet to have broad discretion to determine the design of the election system." On such basis, the majority opinion set forth that the Constitution is construed to allow the Diet to take into consideration factors other than securing equality in the number of voters or population per member to the greatest possible extent, as long as it is reasonable to do so. It further stated that there was no longer a constituency with the disparity of 2 to 1 or higher as compared with the constituency with the smallest number of voters as of the day of the Election due to the following reasons: the 2016 Amendment Act adopted the Adams' method; and the reapportionment of constituencies involving no increase in any prefecture and one decrease each in six prefectures was to be implemented and the demarcation of constituencies was to be revised as measures for correcting disparity until seats are apportioned by that method. Thus, the majority opinion made the evaluation that the state contrary to the requirement of equality in the value of votes was eliminated.

4. However, I cannot agree with the idea of the majority opinion set forth in 3. above.

The House of Representatives, in light of its powers, the term of office of its members, the presence of its dissolution system, and other factors, is required to properly gather and reflect the will of the people. For this reason, the Constitution guarantees equality in the value of votes at a level of nearly 1 to 1, and this serves as the most important and essential criterion.

I do not deny that the Diet is allowed to have discretion to specify the number of seats, the constituencies, the method of voting and other matters concerning elections of members of the respective Houses of the Diet. However, as the equality in the value of votes of nearly 1 to 1 as guaranteed by the Constitution is an important and essential criterion, when deciding the apportionment of seats and demarcation of constituencies, the other factors can only be taken into account if they are reasonable to the extent that does not violate the aforementioned criterion, and I find it difficult to construe that consideration factors that would go beyond the equality in the value of votes of nearly 1 to 1 as guaranteed by the Constitution and would result in allowing a disparity of approximately 2 to 1 fall within the discretion allowed to the Diet. The details are as explained below, and as a result, I consider that the Provisions on Demarcation are unconstitutional.

(1) First, the disparity in the number of voters between constituencies in the Election remained below 2 to 1 at maximum. However, among the total of 289 constituencies, the disparity proved to be 1.9 to 1 or higher for 28 constituencies, 1.8 to 1 or higher for 71 constituencies, and 1.5 to 1 or higher for 168 constituencies. Although the maximum disparity remained below 2 to 1, there is a large number of constituencies that show a considerably wide gap from the equality of 1 to 1, and the Diet is not likely to have explained the policy purposes and grounds regarding such size of the gap and the presence of many constituencies that show a wide gap.

Article 3, paragraph (1) of the New Act for Establishment of the Demarcation Council, which was established ahead of the Election, provides that the disparity in population between constituencies should not be 2 to 1 or higher, but in light of the constitutional requirement of equality in the value of votes, said paragraph cannot be construed to automatically accept the occurrence of a large number of constituencies that show a disparity of almost 2 to 1.

(2) Second, ever since the combined election system of single-seat constituencies and proportional representation was introduced for general elections of members of the House of Representatives, the procedure adopted for apportioning seats for members to be elected from single-seat constituencies has been to first apportion seats to prefectures, and then demarcate the specific constituencies by subdividing the apportioned seats and demarcating constituencies so that each constituency corresponds to one seat. However, a tendency where the value of vote per voter is lower in populous prefectures as compared to less populous prefectures has continued for a long time from the start.

One reason for the continuance of such disparity may be the existence of an idea to increase the number of seats in less populous prefectures with the aim of enabling less populous prefectures, which find it difficult to make their voices heard, to have their voices reach the Diet. However, members of the Diet are representatives of all the people (the Preamble and Article 43, paragraph (1) of the Constitution), and not servants of their own constituencies, they are required under the Constitution to conduct activities from the perspective of all the people, irrespective of the constituencies in which they were elected. The facts that industries, economies, etc. of less populous regions are important and have enormous influence on Japan as a whole, and that information on the various circumstances of less populous regions has come to be transmitted more easily than before due to the recently advanced communication technology, are often reported in the media as manifestations of issues associated with an aging society with fewer children. Therefore the situation of less populous regions has come to be known to both Diet members and citizens. As we can learn about the situation of less populous regions without having to adopt a method of increasing the number of seats in those regions, a practice of apportioning a larger number of seats to less populous prefectures cannot be found to be reasonable. Apart from the population size of each prefecture, there are various other factors making it difficult to reflect opinions of certain voters, such as young people and minorities, due to their small numbers, and it is not possible to reasonably take into account all of these factors in an election. However, the Constitution should not be considered to allow the equality in the value of votes of nearly one person one vote to be impaired by specially taking into account only the factor of population size.

(3) Third, the 2011 Grand Bench Judgment determined that the part of the criteria for demarcation specified by the Former Act for Establishment of the Demarcation Council which pertains to the rule of reserving one seat per prefecture was in a state contrary to the constitutional requirement of equality in the value of votes. However, the judgment did not indicate that it would be sufficient to formally delete Article 3, paragraph (2) of said Article, which provided for the rule of reserving one seat per prefecture, but instead held that the apportionment of seats and demarcation of constituencies which are practically conducted according to the rule of reserving one seat per prefecture and are in a state contrary to the constitutional requirement of equality in the value of votes violate the requirement of the Constitution.

Although law amendments and revision of demarcation were conducted after the 2011 Grand Bench Judgment, the apportionment of seats based on the former criteria for demarcation has not been reviewed in 36 prefectures other than the total of 11 prefectures in which the number of constituencies was reduced by one each. Therefore, the apportionment of seats at the time of implementation of the Election was practically different from a case where seats were reapportioned after abolishing the rule of reserving one seat per prefecture, and it cannot be said that the Election was conducted under an election system compliant with the constitutional requirement of equality in the value of votes.

5. Next, I will study whether or not the aforementioned state in contrary to the Constitution was corrected within a reasonable period of time as required by the Constitution.

The 2011 Grand Bench Judgment held that "The rule of reserving one seat per prefecture has been the major factor causing such a disparity between constituencies in terms of the value of votes, or to put it another way, unreasonableness of said rule has come to the surface in the form of the disparity in the value of votes" (Reason 4(3)). After this judgment was handed down, Article 3, paragraph (2) of the Former Act for Establishment of the Demarcation Council, which provided for the rule of reserving one seat per prefecture, was abolished, but as mentioned in 4. above, the demarcation of constituencies, which had been determined by said judgment to be in a state contrary to the Constitution, was practically maintained for many constituencies, and it could not be said that the unconstitutional state pointed out by said judgment was eliminated. Thus, the start of the reasonable period pertaining to correction of the state contrary to the requirement of equality in the value of votes with regard to the Election is construed to be March 23, 2011, which is the day on which said judgment was handed down.

Six years and six months had already passed from that date before the implementation of the Election, and if the legislative branch had seriously acted toward realizing the equality in the value of votes based on the purport of the determination by the judicial branch, it would have been quite possible to correct apportionment of seats and demarcation of constituencies to achieve the equality of near 1 to 1 in accordance with the constitutional requirement of equality in the value of votes within the period mentioned above, and it should be said that the reasonable period as required by the Constitution had passed.

6. Due to the above, it should be said that the Provisions on Demarcation and the Demarcation of Constituencies were illegal as a whole at the time of the Election. However, a study is required to determine whether the Election should be found to be invalid.

The Election was the first election in which the maximum disparity fell below 2 to 1 since suits to seek invalidation of elections of members of the House of Representatives came to be filed on the basis of inequality in the value of votes. This can be evaluated as a result of the Diet having made extensive efforts toward correcting the disparity, though they were not necessarily sufficient. In addition, Article 3, paragraph (2) of the New Act for Establishment of the Demarcation Council introduced a provision to adopt the Adams' method, and the method is planned to be applied based on the results of the population census to be conducted in 2020. This method derives the number of seats by dividing the population of a prefecture by a certain standard population, and rounding any fractional part of less than one to the nearest integer above, and it is considered to be difficult to expect immediate realization of an election system compliant with the constitutional requirement of equality in the value of votes. However, the disparity in the value of votes between constituencies is expected to narrow for the time being by applying said method, so we would be able to expect the value of votes to approach the equality of 1 to 1.

If so, a process in which the judicial branch does not immediately conclude that the election is invalid, but the Diet first makes efforts to further promote correction of the disparity in the value of votes under the New Act for Establishment of the Demarcation Council and then the judicial branch examines the results is considered to be conformant to the relationship between the legislative power and the judicial power as expected by the Constitution.

For the reasons stated above, in my opinion, the Provisions on the Apportionment of Seats are unconstitutional, but this court should dismiss the claim made by the appellants under the doctrine of judgment in consideration of circumstances for the public interest, and declare that the Election is illegal.

The dissenting opinion by Justice YAMAMOTO Tsuneyuki is as follows.

1. Equality in the value of votes is the sole and absolute criterion

The Constitution of Japan, in its Preamble, provides that: "We, the Japanese people, acting through our duly elected representatives in the National Diet, […], do proclaim that sovereign power resides with the people […] Government is a sacred trust of the people, the authority for which is derived from the people, the powers of which are exercised by the representatives of the people, and the benefits of which are enjoyed by the people." Thus, it declares the principle of sovereignty of the people under a representative democracy. Among the three organs vested with state power, it designates the Diet as the highest organ of state power and the sole law-making organ of the State (Article 41).

Therefore, members of the House of Representatives and the House of Councillors who constitute the Diet, the core of a democratic State, must be elected by a literally fair and impartial election. This logic is represented in Article 43, paragraph (1) of the Constitution, which provides, "Both Houses shall consist of elected members, representative of all the people." Of these elements, "fair election," which is in dispute in the present suit, is an essential constitutional requirement. This is because unless every one of the people can exercise their right to vote equally, the principle of sovereignty of the people underpinned by a representative democracy, which is advocated in the Preamble of the Constitution, would turn out to be pie in the sky. For example, in a national election, if the value of one vote in a particular area is a few times larger than the value of one vote in other areas, the people in the area with votes carrying a larger value would have greater political influence than those in areas with votes carrying a smaller value, based on such difference in value, which is self-evident. Under such circumstances, despite the declaration that sovereignty resides with the people, government established in this manner can never be described as one where "the powers of which are exercised by the representatives of the people, and the benefits of which are enjoyed by the people."

In this sense, when assessing the provisions on the demarcation of constituencies and apportionment of seats for a national election, whether or not equality in the value of votes based on the principle of equality under the law (Article 14) is pursued would be the sole and absolute criterion.

2. An election system causing a level of disparity larger than 20 percent is unconstitutional and void

The majority opinion states as follows: "the Constitution requires that securing equality in the number of voters or population per member to the greatest possible extent should be the most important and essential criterion, but it is understood that the Constitution also allows the Diet to take other factors into consideration as long as it is reasonable to do so. When establishing specific constituencies, it is required that municipalities or other administrative districts created by subdividing prefectures be used as basic units, and while taking into account various factors including the size, population density, composition of residents, transportation conditions and geographical situations of the respective areas, efforts be made to ensure that the will of the people will be reflected properly in the process of carrying out national politics, and at the same time, to reconcile this with the requirement of securing equality in the value of votes. Consequently, determination as to the constitutionality of an election system is to be made by examining whether or not, even when all of these circumstances are comprehensively taken into account, the election system is justified as a reasonable exercise of the discretion vested in the Diet." It may be possible to consider that the Diet is vested with broad discretion. However, in light of the true nature of sovereignty of the people and representative democracy, I consider that equality in the value of votes must be respected first and foremost in every national election as the sole and absolute criterion that takes precedence over everything. Only when this is accomplished can the representative democracy of Japan acquire legitimacy, being equally supported by all the people.

Another view is that in elections of members of the House of Representatives, the disparity in the value of one vote at a level of around 2 to 1 is permissible and if the disparity is kept at such level, equality under the law can be considered to be secured. I cannot agree with this view. When it comes to the case where the disparity in the value of one vote is 2 to 1, if such disparity can be generally observed as leveling off between areas or constituencies through several elections, e.g. the value of one vote in a particular area or constituency in an election is two times larger, but it becomes one half as large in the next election as compared to such value in other areas or constituencies, the situation could narrowly be described as being in conformity with the requirement of equality under the law. However, looking at the attempts made thus far in demarcating constituencies, they have almost always failed to reduce the number of seats in time with regard to areas that experience population outflow, due to which people in these areas always have votes of greater value, while failing to increase the number of seats in time with regard to areas that experience population inflow, due to which people in these areas always have votes of lesser value. This means that people in the latter areas always have less chance to have their voices reflected in national politics, suggesting that a state that is not in conformity with the true nature of a representative democracy continues to exist.

Therefore, I consider that in order to accomplish equality under the law under the current election system for national elections, the principle must be that there will be no disparity in the value of one vote, that is, in comparison between all constituencies, the value of a vote will be always 1.0. I see no harm in regarding this principle as the sole and absolute criterion for national elections. I admit that it may be inevitable that the disparity in the value of votes at a level of around 10 to 20 percent emerges depending on the demarcation of constituencies due to rapid population migration or certain technical reasons. Yet, even in such cases, the permissible level of disparity should be about 20 percent at a maximum, and I consider that an election system that would cause a level of disparity larger than this in the value of one vote is in violation of the provisions of equality under the law and therefore unconstitutional and void.

3. Transitional measures in the case when an election is invalidated

(1) The doctrine of judgment in consideration of circumstances for the public interest has no expressed legal grounds

In this manner, I consider that the value of one vote must be 1.0 in principle, and a disparity at a level of about 20 percent may be inevitable as an exception, but if any higher disparity emerges, the election should be invalidated. In that case, there are two major issues to reflect on: [i] the effect of any decision, etc. made by the House of Representatives or the House of Councillors whose members are elected in an election that is invalidated by a court judgment; and [ii] the status of Diet members elected in an election that is invalidated by a court judgment.

There is a theory for handling these issues in accordance with the doctrine of judgment in consideration of circumstances for the public interest: "even when an election is found to be illegal due to the fact that it was held under the unconstitutional provisions on the demarcation of constituencies and apportionment of seats under the Public Offices Election Act, if there are such circumstances indicated in the judgment due to which the unconstitutional state would not be immediately corrected by rendering a judgment to invalidate the election on the grounds of its illegality, but rather the invalidation of the election could lead to a consequence that is not necessarily in conformity to what is expected by the Constitution, the court should, in accordance with the general rule of law contained in the basis of Article 31, paragraph (1) of the Administrative Case Litigation Act, dismiss claims seeking a judgment to invalidate the election, and declare the illegality of the election in the main text of the judgment" (the aforementioned judgment of the Grand Bench of the Supreme Court of April 14, 1976). However, in a suit challenging the constitutionality of a national election, which is the most important system that supports representative democracy, I very much doubt if the court, while finding the election to be illegal, would be permitted to refrain from invalidating it and only declare its illegality, without any legal grounds to do so. In fact, looking back at the developments to date, even after the several legal revisions and discussions at the Diet concerning the demarcation of constituencies and apportionment of seats, equality in the value of one vote, which is the core principle of a representative democracy, has not been completely accomplished, and the process for improving such a situation has made little progress. In view of this, the court, as the organ with a mission to ensure the constitutionality of an election system, must invalidate an election if it clearly finds it to be unconstitutional, and I consider that the court, at the same time, has the authority to transitionally decide how to deal with issues that may arise from invalidating the election.

(2) The effect of any decisions, etc. that have already been made

For example, as for the first of the two issues mentioned above, i.e. the "effect of any decision, etc. made by the House of Representatives or the House of Councillors whose members are elected in an election that is invalidated by a court judgment," since a court judgment to invalidate an election only has a prospective effect and is not effective retrospectively, it goes without saying that there is no room for such judgment to have any influence on a decision, etc. made by the Diet before the judgment is rendered, and such decision, as a matter of course, continues to be effective.

In addition, even after a court judgment to invalidate an election is rendered, including the period until a new election system designed to accomplish equality in the value of votes is established in response to said judgment and the House of Councillors or the House of Representatives is formed with members elected in an election held under the new election system, each House composed of a certain number of members who continue to hold office will be able to make effective decisions, etc., as explained later. In this respect, there is no possibility of turmoil in national politics. Furthermore, even in such a case where, immediately after a judgment to invalidate an election is rendered, the House, composed of the same members as those who held office before said judgment, makes any decision, etc., such decision, etc. should be treated as effective in order to avoid turmoil in national politics.

(3) The status of Diet members elected in an election that is invalidated

As for the second of the two issues mentioned above, i.e. the "status of Diet members elected in an election that is invalidated by a court judgment," in the case of the House of Representatives, if the court renders a judgment to invalidate an election, it should be construed that, among the members elected from the constituencies subject to the suit, all the members elected from the constituencies where the value of one vote (represented by the number calculated by dividing the number of eligible voters per member in each constituency by the national average of eligible voters obtained by dividing the total number of eligible voters in all constituencies by the total number of seats apportioned thereto; the same applies hereinafter) falls below 0.8 would lose their status as members of the House. This is because it may be impermissible in the first place to enable members elected from constituencies where the value of one vote is smaller than the permissible level of 0.8 to maintain their status and join business at the plenary sessions or committees of the Diet together with members elected from other constituencies. As for members elected from other constituencies, the invalidation of the election does not affect their status as members and they may continue to be members of the House of Representatives until the expiration of their term of office or dissolution of the House. According to this approach, the House of Representatives would transitionally be composed solely of members elected from the constituencies where the value of one vote is 0.8 or larger, combined with members elected from the constituencies excluded from the scope of the suit if any constituencies are thus excluded. The House composed of these members would be required to make a law to specify a new method for the demarcation of constituencies and thereby accomplish equality in the value of one vote. If it is impossible for the House to be comprised of these members, an emergency session of the House of Councillors should be held at the request of the Cabinet, as in the case where the House of Representatives is dissolved (Article 54 of the Constitution), and at the emergency session, the House of Councillors should make a law to specify a new method for the demarcation of constituencies, under which the next election of members of the House of Representatives should be held.

(Note 1) According to the estimate based on the electoral register (including overseas voters) as of October 22, 2017, among the 289 members of the House of Representatives to be elected from single-seat constituencies, 55 members are considered to have been elected from the constituencies where the value of one vote falls below 0.8, and considering that the total number of members is 465, even if these members lose their status and leave the House, it would have no particular influence on the composition of members of the House.

(Note 2) On the other hand, in the case of the House of Councillors, if the legality of the election is challenged in a suit with respect to all constituencies, all of the members who were elected from the constituencies in which the election was invalidated due to the value of one vote falling below 0.8 would lose their status, whereas the members elected from other constituencies would maintain their status as members and may continue to be members of the House of Councillors until the expiration of their term of office, despite the invalidation of the election. Since an election takes place for half the members of the House of Councillors every three years (Article 46 of the Constitution), this approach will make it possible for the House of Councillors to continue its activities and also to hold an emergency session when necessary.

4. An election system designed to accomplish equality in the value of one vote

How to demarcate constituencies in order to accomplish equality in the value of one vote should of course be fully discussed at the Diet when making a law to specify a new method of demarcation of constituencies or apportionment of seats. There is concern that it would be extremely difficult or practically impossible to formulate a policy for demarcation as long as a prefecture or its subdivided area, i.e. a municipality or any other administrative district, is used as a basic unit of the constituency. The biggest obstacle is a prefecture, and its subdivided area, i.e. a municipality or any other administrative district, can also be a significant obstacle.

Therefore, these types of jurisdiction or subdivision should no longer be used as a basic unit of constituency. Rather, constituencies should be demarcated by further dividing these subdivisions into, for example, areas set up for each polling station, or conversely, by treating the whole area of the country as a single constituency or dividing it into several large blocks and setting the number of seats to be apportioned. I consider that equality in the value of one vote can only be accomplished by adopting one of these two methods.
Justice OTANI Naoto

Justice OKABE Kiyoko

Justice ONIMARU Kaoru

Justice YAMAMOTO Tsuneyuki

Justice YAMASAKI Toshimitsu

Justice IKEGAMI Masayuki

Justice KOIKE Hiroshi

Justice KIZAWA Katsuyuki

Justice KANNO Hiroyuki

Justice YAMAGUCHI Atsushi

Justice TOKURA Saburo

Justice HAYASHI Keiichi

Justice MIYAZAKI Yuko

Justice MIYAMA Takuya

Justice MIURA Mamoru
(This translation is provisional and subject to revision.)