2013.09.04

2012 (Ku) 984

Minshu Vol. 67, No. 6

Decision concerning whether the provision of the first sentence of the proviso to Article 900, item (iv) of the Civil Code, is in violation of Article 14, paragraph (1) of the Constitution

Case of special appeal against the ruling that dismissed the appeal filed against the ruling on the division of estate

Decision of the Grand Bench, quashed and remanded

Tokyo High Court, Decision of June 22, 2012

1. The provision of the first sentence of the proviso to Article 900, item (iv) of the Civil Code was in violation of Article 14, paragraph (1) of the Constitution as of July 2001 at the latest.

2. The judgment made by the Supreme Court to the effect that the provision of the first sentence of the proviso to Article 900, item (iv) of the Civil Code was in violation of Article 14, paragraph (1) of the Constitution as of July 2001 at the latest has no effect on any legal relationships that have already been fixed by rulings or other judicial decisions on division of estate, agreements on division of estate or other agreements, etc. made on the assumption of the provision of the first sentence of the proviso to said item with regard to other cases of inheritance that have commenced during the period after July 2001 until said judgment is made.
(There are concurring opinions concerning 1 and 2.)

(Concerning 1 and 2) Article 14, paragraph (1) of the Constitution, Article 900 of the Civil Code; (Concerning 2) Article 81 of the Constitution

Constitution
Article 14
(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 81
The Supreme Court is the court of last resort with power to determine the constitutionality of any law, order, regulation or official act.

Civil Code
(Statutory Share in Inheritance)
Article 900 If there are two or more heirs of the same rank, their shares in inheritance shall be determined by the following items:
(i) if a child and a spouse are heirs, the child's share in inheritance and the spouse's share in inheritance shall be one half each;
(ii) if a spouse and lineal ascendant are heirs, the spouse's share in inheritance shall be two thirds, and the lineal ascendant's share in inheritance shall be one third;
(iii) if a spouse and sibling(s) are heirs, the spouse's share in inheritance shall be three quarters, and the sibling's share in inheritance shall be one quarter;
(iv) if there are two or more children, lineal ascendants, or siblings, the share in the inheritance of each shall be divided equally; provided that the share in inheritance of an child out of wedlock shall be one half of the share in inheritance of a child in wedlock, and the share in inheritance of a sibling who shares only one parent with the decedent shall be one half of the share in inheritance of a sibling who shares both parents.

The decision in prior instance is quashed.
The case is remanded to the Tokyo High Court.

Concerning Reason for Appeal I argued by Appellant Y1 and Reason for Appeal III (2) argued by the appeal counsel for Appellant Y2, ODAWARA Masayuki, SHIKADA Masashi, and YAGYU Yukiko
1. Outline of the case
In this case, with regard to the estate of P, who died in July 2001, the appellees who are P's children born in wedlock (including P's heir(s) per stirpes) filed a petition for a ruling on the division of P's estate against the appellants, who are P's children born out of wedlock.
The court of prior instance determined that the part of the proviso to Article 900, item (iv) of the Civil Code, which provides that the share in inheritance of a child born out of wedlock shall be one half of the share in inheritance of a child born in wedlock (hereinafter this part shall be referred to as the "Provision"), was not in violation of Article 14, paragraph (1) of the Constitution, and concluded that P's estate should be divided based on the respective statutory shares in inheritance of the appellees and the appellants as calculated by applying the Provision.
Appellant Y1 and the appeal counsel for Appellant Y2 argue that the Provision is in violation of Article 14, paragraph (1) of the Constitution and therefore void.

2. Criteria for judging the consistency with Article 14, paragraph (1) of the Constitution
Article 14, paragraph (1) of the Constitution provides for equality under the law, and this provision should be interpreted as prohibiting any discriminatory treatment by law unless such treatment is based on reasonable grounds in relation to the nature of the matter. This is the case law established by the precedent rulings of this court (1962 (O) No. 1472, judgment of the Grand Bench of the Supreme Court of May 27, 1964, Minshu Vol. 18, No. 4, at 676; 1970 (A) No. 1310, judgment of the Grand Bench of the Supreme Court of April 4, 1973, Keishu Vol. 27, No. 3, at 265, etc.)
The inheritance system sets rules as to who is to inherit the property of the decedent, and in order to define the inheritance system, the circumstances in each country such as the tradition, social conditions and public sentiments should be taken into consideration. Furthermore, since the modern inheritance system is closely related to the concept of a family, it cannot be defined without ignoring the rules, people's perceptions, etc. regarding marital or parent-child relationships in the country. It is left to the reasonable discretion of the legislature to define the inheritance system while comprehensively considering all these factors. The major issue disputed in the present case is, within the inheritance system defined in that manner, whether or not the distinction made by the Provision in terms of the statutory shares in inheritance between children born in wedlock and children born out of wedlock constitutes discriminatory treatment without reasonable grounds. If there is no reasonable ground for making such distinction even when the abovementioned discretionary power vested in the legislative body is taken into consideration, it is appropriate to construe that said distinction is in violation of Article 14, paragraph (1) of the Constitution.

3. Whether or not the Provision is consistent with Article 14, paragraph (1) of the Constitution
(1) Article 24, paragraph (1) of the Constitution provides that "Marriage shall be based only on the mutual consent of both sexes and it shall be maintained through mutual cooperation with the equal rights of husband and wife as a basis," and paragraph (2) of said Article provides that "With regard to choice of spouse, property rights, inheritance, choice of domicile, divorce and other matters pertaining to marriage and the family, laws shall be enacted from the standpoint of individual dignity and the essential equality of the sexes." In accordance with these provisions, Article 739, paragraph (1) of the Civil Code provides that "Marriage shall take effect upon notification pursuant to the Family Registration Act," thus adopting the principle of legal marriage and rejecting de facto marriage. Meanwhile, with regard to the inheritance system, the Civil Code was partially revised by Act No. 222 of 1947 (hereinafter referred to as the "1947 Civil Code revision"), abolishing the right to succeed to the position of the head of the family, which had been the foundation for the Japanese "family" system, and introducing the present inheritance system wherein, as a rule, the spouse and child(ren) of the deceased shall be heirs. Still, the clause providing that in the case of inheritance that commences upon the death of a family member, the statutory share in inheritance of a child born out of wedlock shall be one half of that of a child born in wedlock (the proviso to Article 1004 of the Civil Code prior to the 1947 Civil Code revision) survived and was maintained as the Provision in the existing Civil Code.
(2) The decision of the Grand Bench of the Supreme Court on 1991 (Ku) No. 143, July 5, 1995, Minshu Vol. 49, No. 7, at 1789 (hereinafter referred to as the "1995 Grand Bench Decision") took into consideration that the provisions concerning the statutory share in inheritance, including the Provision, do not require that inheritance be conducted according to the statutory share in inheritance of each heir, but function as supplementary rules to be applied in cases such as in the absence of designation of the shares in inheritance by a will. Then, according to the criteria for judgment of the same effect as those shown in 2. above, the Supreme Court accounted for the purport of the Provision, which sets the statutory share in inheritance of a child born out of wedlock as one half of that of a child born in wedlock, holding as follows: "As long as the Civil Code adopts the principle of legal marriage, the Provision gives preferential treatment to the spouse who has been in a marital relationship with the deceased and their child(ren) in terms of the statutory share in inheritance, while at the same time, it assures that a child born out of wedlock will have a certain statutory share in inheritance so as to protect such child." In conclusion, the Supreme Court ruled that the Provision cannot be regarded as going beyond the bounds of the reasonable discretion vested in the legislature and therefore it cannot be deemed to be in violation of Article 14, paragraph (1) of the Constitution.
However, even under the principle of legal marriage, the issue of how to set rules for the statutory share in inheritance of a child born in wedlock and that of a child born out of wedlock should be determined by comprehensively considering the matters referred to in 2. above, and these matters change along with times. Therefore, the reasonableness of such rules should be subject to constant examination and scrutiny in light of the Constitution, which provides for individual dignity and equality under the law.
(3) With regard to important matters among those referred to in 2. above, the factual circumstances have changed as outlined below since the 1947 Civil Code revision.
A. Looking at the process of the 1947 Civil Code revision, it may be seen as the background factors that there was an ethos among people aspiring to have the legitimate descendants inherit their family estate even after the abolition of the right to succeed to the position of the head of the family that had supported the Japanese traditional "family" system, and that there was also a sense of discrimination among people toward men and women in relationships other than legal marriage and children born in such relationships, while regarding only legal marriage as legitimate marriage and respecting and trying to protect it. Furthermore, in the Diet sessions in which the revision bill was deliberated, the existence of laws in other countries at that time, which made a distinction in terms of the share in inheritance between children born in wedlock and children born out of wedlock (such as by denying shares in inheritance to children born out of wedlock), was repeatedly argued as the grounds for supporting the consistency of the Provision with Article 14, paragraph (1) of the Constitution. This suggests that these laws of other countries had an influence on the process of introducing the Provision in the existing Civil Code.
However, since the 1947 Civil Code revision, the actual state of marriage and family in Japan has changed along with the changes in social and economic circumstances, and it is said that people's perceptions of marriage and family have also changed accordingly. Although there may be differences by region or type of work, a family composed of husband and wife and their children who have not grown up became the common minimum unit to support workers' lives and the number of families of such composition increased amid the rapid economic development in the post-war period. At the same time, along with the progress in aging of the population, it has become increasingly necessary to provide security for the lives of surviving spouses, bringing about a drastic change to the significance of inheritance property, which had largely served as the means of living of the descendants. This led to the increase in the spouse's statutory share in inheritance, which is included in the partial revision to the Civil Code by Act No. 51 of 1980. Moreover, the number of children born out of wedlock had been on a declining trend until around 1979, but then it took an upward turn and has been continuing to increase until today. Since the beginning of the Heisei era (from 1989), more people tend to marry later or choose not to marry, and the birth rate has continued to decline. Along with these trends, there has been an increase in the number of households wherein middle-aged single children live with their parents and the number of single-person households, and there has also been an increase in the number of divorces, and, in particular, the numbers of divorces and remarriages involving minor children. In view of these facts, it is said that the forms of marriage and family have greatly diversified, and people now have diversified perceptions of marriage and family accordingly.
B. There has also been a dramatic change in the situations in other countries, which had an influence on the process of introducing the Provision in the existing Civil Code as mentioned in A. above. In other countries, and in the United States and European countries in particular, there used to be a strong sense of discrimination against children born out of wedlock due to religious reasons. At the time of the 1947 Civil Code revision, a tendency to award only a limited share in inheritance to children born out of wedlock was seen in many countries, and this had an influence on the process of introducing the Provision. However, since the late 1960s, most of these countries promoted equal treatment between children born in wedlock and children born out of wedlock from the perspective of protecting children's rights and enacted laws to abolish discrimination in terms of inheritance. At the time when the 1995 Grand Bench Decision was rendered, among the major countries where such discrimination still existed, Germany enacted Erbrechtsgleichstellungsgesetz (Act on Equalization of Succession Rights) in 1998, and France enacted Loi n属 2001-1135 du 3 decembre 2001 relative aux droits du conjoint survivant et des enfants adulterins et modernisant diverses dispositions de droit successoral (Law No. 2001-1135 of December 3, 2001 on the Rights of the Surviving Spouse and Children Born out of Wedlock and Modernizing Various Provisions of Inheritance Law) in 2001, thereby eliminating discrimination in terms of the share in inheritance between children born in wedlock and children born out of wedlock. At present, among the United States and European countries, no country maintains a distinction in terms of the share in inheritance between children born in wedlock and children born out of wedlock, as Japan still does. Thus, such treatment can be said as being rare on a global scale.
C. Japan ratified the International Covenant on Civil and Political Rights (ICCPR) in 1979 (Treaty No. 7 of 1979) and the Convention on the Rights of the Child (CRC) in 1994 (Treaty No. 2 of 1994). These treaties provide that children must be protected against discrimination of any kind by birth. Furthermore, as organizations affiliated with the United Nations, the United Nations Human Rights Committee was established under the ICCPR and the Committee on the Rights of the Child was established under the CRC. These committees are vested with the authority to express opinions, make recommendations, etc. to the contracting States with regard to matters such as the status of implementation of the respective covenant and convention.
As for the status of implementation of the ICCPR and the CRC by Japan in relation to treatment of children born out of wedlock, the United Nations Human Rights Committee made a comprehensive recommendation in 1993 that Japan should remove the discriminatory provisions relating to children born out of wedlock, and since then, both committees have repeatedly expressed concerns, recommended legal revision, etc. to Japan, specifically criticizing the discriminatory provisions relating to nationality, family register, and inheritance, including the Provision. Recently, in 2010, the Committee on the Rights of the Child again expressed its concern about the existence of the Provision.
D. Under the changing global circumstances as described in B. and C. above, the Japanese legal systems, etc. relating to the distinction between children born in wedlock and children born out of wedlock have also changed. In 1988, an action was brought against the requirement of making an entry of a child's relationship with the head of his/her household in his/her residence certificate. In 1994, while this case was pending before the court of second instance, the Guidelines for Handling Affairs Relating to the Basic Resident Registers were partially revised (Jichi-Shin Notice No. 233 of December 15, 1994), and, as a result, it was provided that a child of the head of the household shall be indicated simply as a "child," irrespective of whether the child is born in wedlock or out of wedlock. In addition, another action was brought in 1999 against the requirement of making an entry of the relationship of a child born out of wedlock with his/her mother or father in the family register. In 2004, after the court of first instance rendered a judgment on this case, the Ordinance for Enforcement of the Family Register Act was partially revised (Ordinance of the Ministry of Justice No. 76 of 2004), and, as a result, it was provided that a child born out of wedlock must be indicated in the same manner as a child born in wedlock, for example, the "first son/daughter." With regard to the indication of the relationship of a child born out of wedlock with his/her mother or father already entered in the family register, it was announced by a circular notice (Circular Notice Min-Ichi No. 3008 of November 1, 2004, issued from the Director-General of the Civil Affairs Bureau) that such indication should be corrected according to the new rule mentioned above upon request. Furthermore, in 2006 (Gyo-Tsu) No. 135, the judgment of the Grand Bench of the Supreme Court of June 4, 2008, Minshu Vol. 62, No. 6, at 1367, the court declared that Article 3, paragraph (1) of the Nationality Act (prior to the revision by Act No. 88 of 2008), which provided for different rules for the treatment of children born out of wedlock from that of children born in wedlock in terms of acquisition of Japanese nationality, had been in violation of Article 14, paragraph (1) of the Constitution as of 2003 at the latest. When said revision was made to the Nationality Act in response to this Supreme Court judgment, children born out of wedlock who had made a notification for acquisition of Japanese nationality before 2003 were deemed to be entitled to acquire Japanese nationality.
E. The necessity to equalize the statutory share in inheritance of children born in wedlock and that of children born out of wedlock had been recognized earlier on. In 1979, the Counsellor's Office of the Civil Affairs Bureau of the Ministry of Justice released a draft outline of the Civil Code revision relating to inheritance as an outcome of the deliberation at the Personal Status Law Subcommittee of the Civil Law Committee of the Legislative Council of the Ministry of Justice, in which the office proposed equalization between the statutory share in inheritance of children born in wedlock and that of children born out of wedlock. In addition, said office released a draft outline of the Civil Code revision relating to the marriage system, etc. in 1994 also as an outcome of the deliberation at said subcommittee, and the Legislative Council reported to the Minister of Justice an outline of a bill for partial revision of the Civil Code in 1996, and in these documents, it was clearly stated that the statutory share in inheritance should be equalized for both categories of children. Furthermore, in 2010, the government prepared a revision bill addressing the same point as the abovementioned outlines of the bill with a view to submitting it to the Diet, but neither of them actually reached the Diet.
F. As a result of the revisions made as explained in D. above with regard to the matters for which the abovementioned committees had expressed concerns, recommended legal revision, etc., the distinction in treatment between children born in wedlock and children born out of wedlock has been largely eliminated, but the revision to the Provision has not been achieved yet. Looking at the reasons for this situation, one would notice the following facts. In the United States and most European countries, children born out of wedlock account for a large share in all new born children, and in some countries, the share of these children exceeds 50 percent. In Japan, in contrast, although the percentage of children born out of wedlock has been increasing every year, the number of such children was only slightly over 23,000 in 2011, accounting for only about 2.2 percent in all new born children. In addition, couples' decision to submit a notification of marriage seems to be closely dependent on the pregnancy of their first child. Thus, one possible reason for the abovementioned situation in Japan may be that Japanese people as a whole tend to avoid having children born out of wedlock, or in other words, despite the fact that people's perceptions regarding family are said to have become diversified, the attitude to respect legal marriage seems to still widely prevail among Japanese people.
However, the reasonableness of the Provision, which sets the statutory share in inheritance of a child born out of wedlock as one half of that of a child born in wedlock, is a question of law which should be determined while taking various factors into comprehensive consideration and examining whether or not the Provision unduly violates any rights of children born out of wedlock in light of the Constitution that provides for individual dignity and equality under the law. None of the factors mentioned above, namely, the wide prevalence of the attitude to respect legal marriage, the actual number of children born out of wedlock, and the percentage of such children in Japan as compared to that in other countries, can be regarded as being directly associated with the answer to the abovementioned question of law.
G. Since it rendered the 1995 Grand Bench Decision, this court has ruled that the Provision is in conclusion consistent with the Constitution. However, upon rendering the 1995 Grand Bench Decision, five Justices already pointed out in their dissenting opinion that more weight should be attached to the position of children born out of wedlock, and moreover, said decision was also accompanied by a concurring opinion given by one Justice stating that the Provision which had been reasonable at the time of the 1947 Civil Code revision was becoming no longer reasonable, in view of the changes in the forms of marriage and parent-child relationship or family relationship, as well as the changes in the international circumstances. Opinions to the same effect have also been attached repeatedly by individual Justices to the subsequent petty bench judgments and decisions (see 1999 (O) No. 1453, judgment of the First Petty Bench of the Supreme Court of January 27, 2000, Saibanshu Minji No. 196, at 251; 2002 (O) No. 1630, judgment of the Second Petty Bench of the Supreme Court of March 28, 2003, Saibanshu Minji No. 209, at 347; 2002 (O) No. 1963, judgment of the First Petty Bench of the Supreme Court of March 31, 2003, Saibanshu Minji No. 209, at 397; 2004 (O) No. 992, judgment of the First Petty Bench of the Supreme Court of October 14, 2004, Saibanshu Minji No. 215, at 253; 2008 (Ku) No. 1193, decision of the Second Petty Bench of the Supreme Court of September 30, 2009, Saibanshu Minji No. 231, at 753, etc.) In particular, the abovementioned judgment of the First Petty Bench of the Supreme Court of March 31, 2003, and rulings made by this court thereafter can be understood as barely maintaining the conclusion in favor of the constitutionality of the Provision, if the concurring opinions attached thereto are taken into consideration.
H. Some of the concurring opinions attached to this court's previous rulings mentioned in G. above pointed out that in order to revise the Provision, it was necessary to make a comprehensive decision while paying attention to the consistency with other related provisions regarding inheritance, marriage, parent-child relationship, etc. as well as to the entire framework of the family and inheritance system, and caution would be required for setting the time at which such revision was to take effect and defining the scope of application of the revised provision. On the basis of this, said opinions stated that those matters mentioned therein can be achieved appropriately through the legislative measures taken by the Diet or that the Diet was expected to take the necessary legislative measures quickly.
These concurring opinions were expressed probably because of the great impact of the circumstantial factors mentioned in E. above, that is, there were movements toward the review of the Provision intermittently since 1979 and revision bills were drafted before and after the 1995 Grand Bench Decision were rendered. Be that as it may, it is not necessarily clear which elements of the family and inheritance system are associated with the review of the discriminatory treatment against children born out of wedlock in terms of the statutory share in inheritance. The revision bill outline and the revision bill mentioned in E. above included equalization of the statutory share in inheritance between children born in wedlock and children born out of wedlock but did not aim to revise the spouse's share in inheritance or other related elements of the family and inheritance system as a means to achieve such equalization of the statutory share in inheritance. Hence, the necessity to consider the consistency with the related provisions cannot be the reason for maintaining the Provision as a given. The abovementioned concurring opinions cannot be understood as suggesting that it is impossible to declare unconstitutionality of the Provision by way of a judicial decision. In this respect, even if the Provision is declared unconstitutional by way of a judicial decision, it is still possible to achieve balance with the assurance of legal stability, as explained in detail in Section 4 below.
As mentioned in (2) above, the 1995 Grand Bench Decision also took into consideration that the provisions concerning the statutory share in inheritance, including the Provision, function as supplementary rules to be applied in cases such as in the absence of designation of the shares in inheritance by a will. However, in light of such supplementary nature of the Provision, it is not unreasonable at all to equalize the statutory share in inheritance between children born in wedlock and children born out of wedlock, and what is more, in relation to the statutory reserved share, which cannot be violated even by a will, the Provision is apparently a discriminatory rule set by law, and the very existence of the Provision has the risk of provoking a sense of discrimination against children born out of wedlock upon their birth. In consideration of these points, it must be said that the supplementary function that the Provision has as mentioned above is not a material factor in judging its reasonableness.
(4) None of the changes in various matters, etc. associated with the reasonableness of the Provision can solely be a decisive reason for judging the distinction in terms of the statutory share in inheritance under the Provision. However, giving comprehensive consideration to circumstances such as the trends in society seen from the time of the 1947 Civil Code revision up until now, the diversification of the forms of family in Japan and the changes in people's perceptions resulting therefrom, the legislative trends in other countries as well as the content of the treaties ratified by Japan and the criticism given by the committees set up under these treaties, the changes in the legal system, etc. relating to the distinction between children born in wedlock and children born out of wedlock, and the problems, etc. repeatedly pointed out in the rulings handed down by this court thus far, it can be said to be an evident fact that respect for individuals in a family, which is a collective unit, has been recognized more clearly. Even if the legal marriage system itself is entrenched in Japan, it is now impermissible, as a result of such change in the recognition, to cause prejudice to children by reason of the fact that their mother and father were not in a legal marriage when they were born -a matter that the children themselves had no choice or chance to correct. Rather, it can be said that a notion that all children must be given respect as individuals and that their rights must be protected has been established.
Putting all points mentioned above together, it must be said that even in consideration of the discretionary power vested in the legislative body, the distinction in terms of the statutory share in inheritance between children born in wedlock and children born out of wedlock had lost reasonable grounds by the time when P's inheritance commenced as of July 2001 at the latest.
Consequently, it must be concluded that the Provision was in violation of Article 14, paragraph (1) of the Constitution as of July 2001 at the latest.

4. De facto binding force as a precedent
The decision of the present case concludes that the Provision was in violation of Article 14, paragraph (1) of the Constitution as of July 2001 at the latest. It does not intend to modify the conclusion drawn by the 1995 Grand Bench Decision and the subsequent petty bench judgments and decisions mentioned in 3(3)G. above, which affirmed the constitutionality of the Provision at the time of the commencement of inheritance in the earlier cases in which inheritance had commenced before July 2001.
On the other hand, in principle, any law that is in violation of the Constitution is void, and the effect of any action taken in accordance with such law should be annulled. If that is the case, since the Provision is judged by the decision of the present case to have been in violation of Article 14, paragraph (1) of the Constitution as of July 2001 at the latest, the Provision is deemed to have been void from July 2001 and onward due to the de facto binding force as a precedent, and the effect of judicial decisions and agreements, etc. subsequently made in accordance with the Provision would also be annulled. However, the Provision forms part of the Civil Code, which is a fundamental law addressing people's lives and family relationships, and regulates inheritance which takes place as a common phenomenon in everyday life. As about 12 years have passed since July 2001, it is easily presumed that during this period, there have been a number of cases in which division of estate is conducted on the assumption of the constitutionality of the Provision, and new rights and interests have been widely formed on the basis of the results of such division of estate. In particular, the judgment of unconstitutionality of the Provision made by the decision of the present case is the first action taken by this court to declare the Provision to be unconstitutional by reason that the Provision lost its reasonableness in light of the changes in social circumstances over a long period of time. Nevertheless, if the judgment of unconstitutionality made by the decision of the present case is deemed to have a de facto binding force as a precedent and affect the division of estate, etc. conducted thus far, and ultimately have an effect on already solved cases, this would amount to considerable harm to legal stability. Legal stability is a universal requirement inherent in law, and it should therefore be said that the judgment of unconstitutionality made by this court is required to have only a limited binding force as a precedent, thereby achieving balance with the assurance of legal stability. This point could raise an issue in respect of whether or not it is appropriate to declare the Provision to be unconstitutional by way of a judicial decision (see 3(3) H. above).
From the viewpoints explained above, although it is inappropriate to overturn at present such legal relationships that have already been fixed among the parties concerned by means of judicial decisions, agreement, etc., if legal relationships among the parties concerned have not reached that stage, it may be appropriate to make their legal relationships fixed without applying the Provision, which is judged by the decision of the present case to be unconstitutional and void. With regard to divisible claims or divisible obligations which are to be divided according to the statutory share in inheritance upon the commencement of inheritance by operation of law, the application of the provisions concerning the statutory share in inheritance can be an issue in the course of receiving payment from obligors or making payments to obligees. Therefore, it is inappropriate to consider that the legal relationships among the parties concerned have been fixed as a result of the division of such claims and obligations according to the share in inheritance set by the Provision immediately upon the commencement of inheritance. It is rather appropriate to consider that the legal relationships among the parties concerned have been fixed only when it can be said that the dispute among the parties concerned has been settled by the final judicial decision or the explicit or implicit agreement, etc. and there is no need any longer to apply the Provision.
Consequently, it is appropriate to construe that the judgment of unconstitutionality made by the decision of the present case has no effect on any legal relationships that have already been fixed by rulings or other judicial decisions on division of estate, agreements on division of estate or other agreements, etc. made on the assumption of the Provision with regard to other cases of inheritance that have commenced during the period after P's inheritance commenced until the decision of the present case is rendered.

5. Conclusion
For the reasons stated above, with regard to P's inheritance that commenced in July 2001, the Provision should be judged to be inapplicable because it is in violation of Article 14, paragraph (1) of the Constitution and therefore void. The determination of the court of prior instance mentioned above, which is contrary to this conclusion, was made on the basis of the erroneous interpretation of said paragraph and therefore cannot be affirmed. The arguments by Appellant Y1 and the appeal counsel for Appellant Y2 are well-grounded on this point, and without needing to make a determination on other points argued by them, the decision in prior instance should inevitably be quashed. We remand the case to the court of prior instance in order to have the case further examined.

Therefore, the decision has been rendered in the form of the main text by the unanimous consent of the Justices. There are concurring opinions by Justice KANETSUKI Seishi, Justice CHIBA Katsumi, and Justice OKABE Kiyoko, respectively.

The concurring opinion by Justice KANETSUKI Seishi is as follows.
The holding of this court regarding the de facto binding force of this decision, included in the court opinion, is the first holding indicated by this court on that issue, and it will have significance as a general rule for the future and therefore can provoke various arguments. In view of this, I would like to present my understanding on this issue.
How is it possible to validate the view presented in this decision? To consider this question, one should take, as a premise, what is generally referred to as the incidental judicial review system and the doctrine of case-by-case effect when applied to a judgment of unconstitutionality, which have been established as rules for the Japanese judicial review system.
The incidental judicial review system is a system in which the Supreme Court makes a judgment on the issue of constitutionality of a law or regulation to the extent necessary for solving a specific case. The matter raised as an issue in connection with the inheritance disputed in the present case is the provision on the statutory share in inheritance that had a substantive effect at the time when said inheritance commenced. Therefore, the judicial review on this matter should be conducted as of the time of the commencement of that inheritance. Hence, this decision made a judgment on the issue of constitutionality of the Provision as of the time when the inheritance disputed in the present case commenced.
Under the doctrine of case-by-case effect, a judgment of unconstitutionality is effective only with regard to the case concerned, and even a judgment of unconstitutionality made by the Supreme Court does not have such effect as generally nullifying the provision that it has judged to be unconstitutional. Therefore, unless such provision is removed from a law or regulation or revised by legislation, courts in charge of other cases have to make a judgment on the issue of constitutionality while taking the existence of said provision as a given. Thus, the Supreme Court's judgment of unconstitutionality under the doctrine of case-by-case effect only has a de facto binding force as a precedent in relation to other cases. Admitting that, since it is judged by the Supreme Court that the Provision was in violation of Article 14, paragraph (1) of the Constitution at the time of the commencement of the inheritance disputed in the present case at the latest, it would be appropriate, from the perspective of equal application of law, for courts in charge of other cases addressing the inheritance that commenced thereafter to judge the Provision to be unconstitutional in accordance with said judgment by the Supreme Court. In this sense, the judgment of unconstitutionality made by this decision is effective retroactively in principle.
However, the de facto binding force as a precedent is admitted in order to meet the request of fair and equal application of law by giving the same solution to the same type of cases. Assuming so, an exception to such binding force based on reasonable grounds may be allowed as in the case that the principle of equality under Article 14, paragraph (1) of the Constitution allows an exception based on reasonable grounds. In addition, the de facto binding force as a precedent is also intended to achieve legal stability by giving the same solution to the same type of cases. If admitting such binding force would rather harm legal stability, its function should be diminished accordingly. As explained in the court opinion, if the judgment of unconstitutionality made by this decision is allowed to affect the effect of the division of estate, etc. already conducted, it would amount to considerable harm to legal stability. In particular, when the Supreme Court makes a judgment of unconstitutionality regarding a law or regulation that the court has previously judged constitutional, as it happens in the present case, annulling the effect of actions already taken while relying on the precedents of earlier cases would cause greater harm to legal stability.
There is a view that whether or not the retroactive effect of a legal interpretation given by the court can be restricted largely depends on issues such as whether the legal interpretation stays within the confines of the discovery of the right law or goes beyond that and functions as the creation of a new law. Indeed, it must be said that an act of defining the scope of application of a specific legal interpretation apart from the case concerned may have something in common with a legislative act. Those who think that a legal interpretation by the court should stay within the confines of the discovery of the right law would be negative about restricting the retroactive effect of a legal interpretation. In the first place, some might question whether it is appropriate for the Supreme Court to indicate its view on how to apply the law in question to other cases.
However, it can be understood that in this decision, the court indicates its holding on this issue, considering that it is inappropriate to judge the Provision to be unconstitutional without showing how to avoid an expected confusion that may arise as a result of such judgment, and thus said holding is closely related to the judgment of unconstitutionality and therefore it should not be regarded merely as obiter dictum. Furthermore, with regard to the view that a legal interpretation by the court must stay within the confines of the discovery of the right law, on actual occasions where the court makes a legal interpretation, it may be difficult in general to avoid accompanying something equivalent to legislation, although the degree and manner of such act would differ depending on the case. In this respect, it may not be appropriate to put such limitation as mentioned above to the method of legal interpretation by the court. In the United States, where the tradition of common law is maintained, prospective overruling is allowed.
Prospective overruling is not an issue to be discussed only in the context of a constitutional judgment, but as mentioned above, the requirement of the assurance of legal stability emerges as a more serious and broad issue in the course of changing a previous constitutional judgment of a provision of a law or regulation. In view of the magnitude of its influence, judicial review of a law or regulation is sometimes made with a reserved attitude, such as interpreting a law or regulation narrowly and constitutionally. Where the Supreme Court restricts the retroactive effect of its judgment of unconstitutionality, it is equal to attempting to limit the scope of such judgment, and in a sense, the Supreme Court can be regarded as showing a reserved attitude to exercise the power to make judicial review.
In any event, since the Supreme Court's judgment of unconstitutionality only has a case-by-case effect, such judgment, including the court's holding on the retroactive effect, is deemed to be effective when it is respected and followed by other courts, etc. as a judgment with a de facto binding effect as a precedent. In this sense as well, it is different from legislation. However, in reality, it is impossible to predict all possible disputes that may arise in the future, and this decision does not exhaustively mention in which case the judgment of unconstitutionality will not have an effect. Therefore, while following the holding indicated in this decision as a guideline, each court will have to try to find an appropriate solution to the case concerned by making a proper judgment on matters, including whether or not it needs to make a judgment of unconstitutionality.

The concurring opinion by Justice CHIBA Katsumi is as follows.
I would like to give some comments with regard to the relationship between the holding included in the court opinion as to the retroactive effect of the judgment of unconstitutionality in the present case, and the power to make judicial review vested in the Supreme Court.
1. The court states in its opinion that the Provision was unconstitutional at the time when the inheritance disputed in the present case commenced at the latest and it has been void thereafter. With regard to the point as to whether the judgment of unconstitutionality in the present case has the de facto binding force as a precedent, the court holds that this judgment of unconstitutionality is not effective in relation to already solved cases, thereby limiting the scope of its effect to a certain extent so as not to cause detriment to legal stability (hereinafter referred to as the "holding on the retroactive effect of the present case").
It is a general understanding that the power to make judicial review vested in the Supreme Court of Japan is subject to the incidental review system and the effect of a judgment of unconstitutionality made through the exercise of this power is governed by the doctrine of case-by-case effect. Based on this understanding, said holding can be regarded as an unusual one because it results in indicating in advance, inter alia, whether or not the judgment of unconstitutionality in the present case has a retroactive effect and to what extent it has such effect as matters relating to how to handle the same type of cases in the future, beyond the bounds of the handling of the specific case concerned, even though it addresses these matters with a view to explaining the de facto binding force as a precedent. However, considering that the action to judge a law or regulation to be unconstitutional and void usually poses a risk of overturning a number of legal relationships, etc. that have been formed in accordance with that law or regulation, the court indicates said holding as a sort of step to avoid such a situation that would considerably harm legal stability. Hence, such holding is basically an explanation that always needs to be given by the Supreme Court when it judges a law or regulation to be unconstitutional and void. In this sense, the holding on the retroactive effect of the present case should be indicated not as obiter dictum but as ratio decidendi.

2. Next, when a legislative action is to be taken to abolish a law or regulation that is judged to be unconstitutional and void, arrangements are expected to be made as necessary with regard to the effective date of the revision law to abolish the law or regulation or the transitional measures by way of attaching supplementary provisions to the revision law, in consideration of matters such as the adverse effect of harming legal stability. The holding on the retroactive effect of the present case is quite similar to this action (the legislative action to make arrangements by way of attaching supplementary provisions to the revision law), and in this respect, there may be a concern that whether such holding is possible or appropriate as a judicial action is called into question.
Since the power to make judicial review that the Constitution vests in the Supreme Court includes laws and regulations as its target, if the Supreme Court judges a law or regulation to be unconstitutional and void, such judgment would have an extensive de facto binding force as a precedent even under the doctrine of case-by-case effect, and it is naturally presumed that a situation that would undermine legal stability might take place unless some kind of measure is taken. Considering this, in order to avoid such a situation, the function to limit, inter alia, cases where a judgment of unconstitutionality should have a retroactive effect, as well as the time from when and to what extent it should be deemed to be effective retroactively, which can be said to be similar to a legislative action to decide matters such as the effective date of the revision law by way of its supplementary provisions, should have been supposed to be included from the beginning in the Supreme Court's power to make judicial review. The holding on the retroactive effect of the present case represents a part of the principle or action that is naturally inherent in the Supreme Court's exercise of its power to make judicial review or that is supportive of a function or system incidental to such exercise of power. It should be understood that the Constitution in advance approves of this as a judicial action in the form of the exercise of the power to make judicial review.

The concurring opinion by Justice OKABE Kiyoko is as follows.
In light of the facts of the case, I would like to give some comments with regard to the issue of the constitutionaltiy of the Provision and the attitude to respect legal marriage in Japan.
1. The 1995 Grand Bench Decision stated that if, as a result of the adoption of the legal marriage system under the Civil Code, children born in wedlock and children born out of wedlock are differentiated and subject to different rules in terms of matters such as the formation of a parent-child relationship, such consequence must be tolerated. As for the requirement for the formation of a parent-child relationship, a child conceived by a wife during marriage shall be legally presumed to be a child of her husband upon birth, without any procedure (Article 772 of the Civil Code). In this respect, such child is different from a child who is born out of wedlock but whose relationship with his/her father is later formed as a result of filiation. This distinction is based on the marital relationship between the mother and the father and is therefore considered to be reasonable. However, the provisions concerning the share in inheritance relate to the effect of a parent-child relationship. The conclusion that children born in wedlock should be given preferential treatment compared to children born out of wedlock cannot be accounted for as a conclusion with logical necessity, in the same sense that the abovementioned requirement for the formation of a parent-child relationship has grounds.
The respect for a marriage is respect for a marital unit involving a child born in the marital relationship. There is a view that the respect for a marital unit necessarily represents respect in terms of the share in inheritance. However, as explained in the court opinion, the inheritance system is defined while taking various matters into comprehensive consideration and these matters change along with the times. Therefore, even if the Civil Code embraces such view and the Provision is a proof of this fact, constant review would be required as to whether or not it is permissible under the Constitution to adhere to the policy of respecting a marital unit in the context of inheritance by awarding a preferential share in inheritance to the decedent's child born in wedlock compared to the same decedent's child born out of wedlock.

2. As the substantive grounds for the idea that a marital unit consisting of husband and wife and their children should be protected, there is a view that property obtained by the married parties during the period of their marriage is in substance property that belongs to the marital unit and it should basically be inherited by their children born in their marital relationship who are members of the marital unit. It is true that husband and wife work and cooperate with each other to maintain their marital unit (husband and wife have a legal obligation to assist each other), and their cooperation would require their long-term, constant endeavor. It is also a fact in society that in most cases, husband and wife respectively work to make a living, do housework, and perform various other things such as socializing with their relatives and neighbors, and in addition to these, they are engaged in bringing up their children, which imposes physical and economic burden on them over a long period of time, and they may also be committed to taking care of their aged parents or other relatives. Children born in wedlock are supported and raised to be grown up through such cooperative work of husband and wife, and normally, the children themselves are in effect expected to provide cooperation to the married couple accordingly, although the children's cooperation to their parents may be different in nature and degree from the cooperation between husband and wife.
This has basically been considered to be a picture of a family in Japan, and the attitude to respect legal marriage can be said to have been widely shared among Japanese people based on such picture of a family. In 1988, when the inheritance on which the 1995 Grand Bench Decision was rendered had commenced, it is considered that the abovementioned picture of a family had prevailed widely and provided support for the reasonableness of the Provision. Even at present, this picture of a family seems to still prevail to a certain extent, and under such circumstances, it is understandable for the members of a marital unit to have a negative feeling about setting the share in inheritance of children born out of wedlock, who do not belong to the marital unit, as equal to that of children born in wedlock, who are members of the martial unit.
However, as pointed out in the court opinion, the abovementioned picture of a family has changed due to various reasons. Moreover, it should be noted that children born out of wedlock do not have a choice to become members of a martial unit from the very beginning of their life. Of course, there are such cases where the mother and father choose not to legally marry of their own will and their children therefore cannot obtain the status of children born in wedlock although in effect they live as a marital unit. However, in most cases, the reality is that children born out of wedlock are placed in the position from the very beginning of their life in which they are deprived of chances to participate in or work to maintain the marital unit even if they want to. It can be said that the changes in circumstances that have occurred in and outside Japan since the 1947 Civil Code revision, as pointed out in the court opinion, have led to establish an idea that children should be respected as individuals, and although there are sufficient grounds for protecting marital units, these changes in circumstances have diminished the reasonableness of the policy of giving preferential treatment to marital units necessarily and generally compared to non-martial units for that purpose, and said changes have ultimately diminished the reasonableness of the policy of awarding a preferential share in inheritance to children born in wedlock, who are members of marital units, compared to children born out of wedlock, who do not belong to marital units, for the purpose of protecting marital units.
From this standpoint, I should say that even though the attitude to respect legal marriage widely prevails among Japanese people as a whole, it is no longer appropriate to make a distinction in terms of the share in inheritance between children born in wedlock and children born out of wedlock.

Justice TAKESAKI Hironobu
Justice SAKURAI Ryuko
Justice TAKEUCHI Yukio
Justice KANETSUKI Seishi
Justice CHIBA Katsumi
Justice YOKOTA Tomoyuki
Justice SHIRAKI Yu
Justice OKABE Kiyoko
Justice OTANI Takehiko
Justice OHASHI Masaharu
Justice YAMAURA Yoshiki
Justice ONUKI Yoshinobu
Justice ONIMARU Kaoru
Justice KIUCHI Michiyoshi