1995.07.05

1991 (Ku) 143

Minshu Vol.49, No.7 at 1789

Decision on the share in the inheritance of an illegitimate child

Case of special appeal against the decision to dismiss the appeal against the decision on the partition of estate

Judgment of the Grand Bench, dismissed

Tokyo High Court, Decision of March 29, 1991

The first part of the qualifying proviso of Article 900, subparagraph 4 of the Civil Code is not in violation of Article 14, paragraph 1 of the Constitution (there are concurring opinions and dissenting opinions)

Article 14, paragraph 1 of the Constitution, Article 900 of the Civil Code

The present appeal is dismissed. The cost of appeal shall be borne by the appellant.

On the grounds for appeal presented by the counsels

The argument of the counsels can be summarised as follows: the first part of the qualifying proviso of Article 900 (hereafter the Provision), subparagraph 4 of the Civil Code which determines the share in inheritance of a child who is not legitimate (hereafter illegitimate child) as half that of the legitimate child is against Article 14, paragraph 1 of the Constitution.
1 Article 14, paragraph 1 of the Constitution provides for equal treatment under law. It is intended to prohibit discrimination without a reasonable ground. Differentiation in the legal treatment on the ground of the difference in economic, social, and other various factual relations concerning individuals is not against this provision, insofar as the differentiation is reasonable (Judgment of the Supreme Court, Grand Bench, May 27, 1964; Minshu 18-4-676, November 18,1962; Keishu 18-9-579).
As a prerequisite of examining this issue, the system of inheritance in Japan is reviewed in the following.
1) The system of traditional family inheritance (katoku-sozoku) was abolished and the system of joint inheritance was introduced by the Law on the Partial Amendment of the Civil Code (Law No.222, 1947), based upon Article 24, paragraph 2 of the Constitution which provides that laws regulating marriage and inheritance etc. should be enacted on the basis of individual dignity and the essential equality of men and women.
Concerning the scope of heirs, the current Civil Code provides that the spouse of the deceased is always an heir (Art. 890), and children of the deceased are also heirs (Art.887) and thus makes it a rule that the spouse and children are heirs. The Code further provides that if there is no children or a person who subrogates the child, the lineal ascendant and the siblings become the heirs of first and second rank respectively (Art.889). The Code also provides for the division of the estate in cases where there are multiple heirs (Art.900, hereafter, statutory shares), and if, among the joint heirs, there is a person who had accepted a gift by testament from the deceased (special beneficiary), this person's share is the remaining amount after deducting this amount from the statutory share (Art.903).
Thus, the deceased may determine the share of joint heirs by testament, but also may give all or part of the assets to the heirs or a third party by testament (Art.964). However, this cannot be effected against the provisions on the statutory reserved portion as provided in articles 1028 and 1044 (qualifying proviso to Art.964), and those who are entitled to such portion may claim the reduction of gift by testament which is against these provisions (Art.1031).
The heirs have a choice of accepting inheritance or not. An heir must fully or conditionally accept the inheritance or waive it within three months of the time he or she learned of the commencement of the inheritance (Art.915).
Article 906 sets out the criteria for the division of the estate in cases of joint inheritance and provides that in dividing the estate, the kinds and nature of the assets and rights which are included in the estate, the age, profession, mental and physical state of health and circumstances of living of each heir should be taken into consideration. Joint heirs may agree on the division of the estate by negotiation (Art.907, para.1), and if they fail to reach an agreement, may request the family court to divide the estate (ibid., para.2). On the other hand, the deceased may determine the means of dividing the estate by testament, or prohibit division for up to five years of the beginning of inheritance (Art.908).
2) The share of the spouse was altered in the way provided by the current Article 900, subparagraphs 1 to 3 by the Law on the Amendment of the Civil Code and the Law on the Family Adjudication of 1980 (Law No.51, 1980). The share of the spouse, where the spouse and child are joint heirs, was altered to one half of the estate (previously one-third), where the spouse and a lineal ascendant of the deceased are joint heirs, two-thirds (previously, one-half), and where the spouse and the siblings are joint heirs, three-quarters (previously, two-thirds).
Also by this amendment, a system of contributory portion was introduced. Thus, the newly inserted Article 904-2, paragraph 1 provides that if, among the heirs, there is a person who made a special contribution to the maintenance of or increase in the assets of the deceased by way of providing work and service for the deceased's business, or proprietary contribution, providing of caring and nursing for the deceased, the estate to be divided equals the assets which the deceased had at the time of the beginning of inheritance reduced by the portion of contribution as determined by the agreement of all heirs. This person's share is the statutory or testamentary share plus the portion of contribution. Paragraph 2 of the same provision provides that if the heirs failed to reach an agreement, or are unable to negotiate, the family court may, upon the request of the person who made the contribution as provided in this provision, determine the portion of contribution by taking into consideration the tim e, means, and extent of contribution, the amount of the estate and all other circumstances. By this system, those who made a special contribution to the maintenance of or increase in the deceased's assets are allowed to receive inheritance above statutory or testamentary share, and thus substantial fairness in inheritance is ensured.
3) As described above, the Civil Code has been amended in accordance with the social change, and has various provisions on the inheritance of the assets of the deceased. Article 900 which provides for statutory shares is merely one of these provisions; it does not make it mandatory to have the estate divided in accordance with the statutory shares. On the contrary, despite the provisions on statutory share, the deceased may choose to determine the share by testament. Heirs who do not wish to accept inheritance may waive inheritance. In cases where the share is discussed between the heirs, the estate does not necessarily have to be divided in accordance with the statutory share. Joint heirs may, by considering the circumstances involving each heir, allow a particular heir to receive more than the statutory share by agreement. However, in cases where the heir cannot reach an agreement on the division of the estate, the family court adjudicates the matter, and the estate has to be divided in accorda nce with the statutory shares.
In this way, provisions on statutory shares of inheritance are designed to operate in a supplementary way in cases such as where there is no designation by testament.
2 The system of inheritance determines by whom and how the assets of the deceased should be inherited. Historically and socially, there are different kinds of inheritance. When designing the system, tradition, social environment, perception of the people, and other factors have to be considered, and the system of inheritance in each country more or less reflects these factors. Furthermore, a contemporary system of inheritance is closely related to the idea of family in a given country, and the system cannot be established without considering the rules of marriage and family in that country. It should be concluded that the way the inheritance system is established is left to the reasonable discretion of the legislature by taking all these into consideration.
As mentioned above, considering the fact that provisions on statutory inheritance shares including this Provision do not provide that inheritance should always be effected in accordance with the statutory shares, but are intended to be applied in a supplementary way in cases such as where there is no designation by testament, differentiation of statutory shares of inheritance between legitimate and illegitimate children in this Provision, insofar as it has a reasonable ground in the reason of enactment and the differentiation is not excessively unreasonable in relation to the reason of enactment, and can be acknowledged as being within the scope of reasonable discretion granted to the legislature, cannot be regarded as an unreasonable discrimination which is in violation of Article 14, paragraph 1 of the Constitution.
3 While Article 24, paragraph 1 provides that marriage is concluded only on the basis of the consent of both sexes, Article 739, paragraph 1 of the Civil Code provides that 'marriage takes effect by filing in accordance with the Law on Civil Status,' and thus excludes de facto marriage and adopts marriage by law. Article 732 prohibits bigamy and declares the system of monogamy. It goes without saying that the system adopted by the Civil Code is not against the above-mentioned provision of the Civil Code.
If, as a result of the adoption of the system of marriage by law by the Civil Code, a legitimate child born from the marriage and an illegitimate child born outside the marriage are differentiated and regulated differently in the establishment of parental relationship, and common law spouses are not entitled to inheritance of the other spouse, this is something which has to be tolerated.

Summary
The aim of enactment of the Provision is understood to be to respect the status of the legitimate child who was born between spouses who are married by law, and at the same time, paying due attention to the status of the illegitimate child, grant a statutory share of one-half of the legitimate child's share in order to protect the illegitimate child, and thus balance the respect of marriage by law and the protection of the illegitimate child. In other words, since the Civil Code has adopted the system of marriage by law, insofar as the statutory inheritance share is concerned, the legitimate child has to be given preference. On the other hand, the illegitimate child was allowed some share and it was intended to protect the illegitimate child.
Since the Civil Code has adopted the system of marriage by law, the reason of enactment of the Provision has a reasonable ground. The fact that the Provision set out the statutory inheritance share of an illegitimate child at one-half that of the legitimate child cannot be regarded as excessively unreasonable in relation to the reason of enactment, and exceeded the scope of reasonable discretion granted to the legislature. The Provision cannot be regarded as an unreasonable discrimination and is against Article 14, paragraph 1 of the Constitution. The argument of the appellant cannot be accepted.
Therefore, the kokoku appeal is dismissed and the cost of the appeal shall be borne by the appellant. There are concurring opinions of justices Itsuo Sonobe, Tsuneo Kabe, Katsuya Onishi, Hideo Chikusa and Shinichi Kawai, and dissenting opinion of justices Toshijiro Nakajima, Masao Ono, Hisako Takahashi, Yukinobu Ozaki, and Mitsuo Endo, while others agree to the main text of the decision.

Concurring Opinion of Justice Kabe
I concur with the majority opinion that the appellants' argument that the Provision on the statutory inheritance share of the illegitimate child is against Article 14, paragraph 1 of the Constitution is without grounds. However, in the light of dissenting opinions which found the Provision to be unconstitutional, supplementing the majority opinion, I would like to express my views as follows.
1 The Civil Code has adopted the system of marriage by law and the system of monogamy, while prohibiting polygamy. It is known that in real life, the way men and women are associated varies and is different according to the country and the time, but the adequacy by law of the adoption of the system of marriage by law and monogamy is not questioned nowadays. The matter at issue is not the adequacy of the system of marriage by law, but the adequacy of the difference in the statutory share of inheritance which inevitably emanates from the system of marriage by law.
A person who has assets may give them away as a gift while he or she is alive, give it by testament, or designate the share of inheritance. In order to address the situation in which such measures are not taken, supplementary provisions on statutory shares of inheritance, including the Provision exist, and the statutory heir of the first rank is the spouse of the deceased. In cases where the spouse and the child are jointly heirs, the statutory share of the spouse has been increased from one third to one half by the amendment by Law No.51 of 1980. Then who is going to inherit the remaining one half? As the leading heir, and in most cases, as a person who has to rely on the estate of the deceased for the income in the later life, this is a matter of utmost interest for the spouse. In Japan, where the primary component of the estate is residential real estate, in the light of the current state of affairs in which prices of real estate are extremely high, this only natural and understandable.
The heir who is entitled to the remaining one half of the statutory share is a child of the deceased, but in such cases, since the law has adopted the system of marriage by law on the basis of monogamy, the law naturally presupposes that the heir who comes second to the spouse is the legitimate child. In reality, the possibility that the child of the deceased is born as an extra-marital child cannot be denied, and extra-marital children should not be ruled out as heirs as children of the deceased (the view which denies inheritance to an illegitimate child is rare in Japan, though this is not the case in some foreign countries). However, it is not easily acceptable to the spouse who built a family with the deceased by marriage by law, if the share of inheritance of the illegitimate child is to be made equal to that of the legitimate child.
Against this view, there is an argument that the emergence of extra-marital (illegitimate) children cannot be prevented by differentiating the share of inheritance between legitimate and illegitimate child. However, the issue here is not an off-hand examination of a purpose/effect argument, i.e. whether making their treatment not necessarily equal (differentiating the share of inheritance) facilitates marriage by law or not. Insofar as the system of marriage by law is adopted, in a way it is a logical outcome of this system that a difference in the share of inheritance emerges between legitimate and illegitimate child.
2. Next, special reference should be made to the traditional family - ie system.
After the War, by the enactment and taking of effect of the Constitution, the system of ie based on the Civil Code before the War was abolished, and the family was transformed from the living community under the head of the family to a family centering around the married couple on the basis of the consent of both parties.
Naturally, a couple married in accordance with law does not always have a child. In such cases, the law presupposes adoption, but from the viewpoint of those who respect the continuity of blood lines, there has to be an heir of the linear descent regardless of the fact of whether this person is intra-marital child or not. The background to such a view is the system of ie. Whether it is along the male line or female line is irrelevant for this need of lineal succession. The present case is a good example.
In this case, the deceased Masa is the only daughter (the son had died earlier, and therefore, she was the only child), and in order to find the successor of the family, trial marriage was repeated for the selection of the groom for adoption. One of the heirs of the child who was born between Masa and the person who failed to reach formal marriage with her claimed a share in the estate of Masa. If there were no child between Masa and the husband who was adopted to the family, this child, who was technically extra-marital, would have succeeded the family line of Masa. This is the system of ie. This system in a way respects extra-marital child in order to maintain and continue the blood line, and it is clear, even without comparing it with the system of family in the Civil Law countries, that the problem of differentiating the share of inheritance between legitimate and illegitimate child has nothing to do with the system of ie.
3 When discussing the constitutionality of the Provision, it is necessary not only to compare the system of Japan and other countries, but also to examine whether the Provision entails violation of Article 14, paragraph 1 of the Constitution in the actual state of disputes under societal conditions in Japan. Of particular significance are the facts concerning the case which is simultaneously examined by this court ((ku) No.302 of 1993). Outline of the case is as follows:
The deceased had a daughter A and sons B and C as illegitimate children and adopted son D who is a son of his former wife, son E, and daughter F, who was born between this former wife and him. Son B married the deceased's sister, succeeded the business and is the core of the family. By the death of the deceased, there was a problem of inheritance. A,C,D, and E assigned their statutory share of inheritance to B and sided with B, F was left alone. B had a share of seven-ninths, while F had two-ninths. The original adjudication ruled in the case initiated by F on the division of the estate that B's residential home and land should not be divided, but instead, B should pay an appropriate adjustment money to F.
Against this decision, B claimed that while the statutory share of inheritance of the six children of the deceased should be equally one-sixth (three-eighteenths) of the estate, regardless of whether they are legitimate or illegitimate children, the amount of adjustment payment is based upon the calculation that F receives two-ninths of the estate, which exceeds this share. B claimed that this payment was against Article 14, paragraph 1 of the Constitution and therefore, appealed against the adjudication. Argument that the Provision is against the equality clause is not compatible with such a concrete dispute.
4. The reality of disputes in the present case and the other case is as above. In general, the actual state of association and marriage of men and women varies considerably. However, in legislative practice, even when the circumstance varies, it is needed to make a clear-cut decision on problems such as whether an extra-marital child should be given the right to inheritance, and if this is acknowledged, whether they should be treated in an equal way as marital (legitimate) children, and if there is to be differential treatment, to what extent differentiation is allowed.
What is at issue in the present case is not the appropriateness of the legislation which denies, as can be seen in the often quoted US cases, the right of the illegitimate child (extra-marital child) as the child of the deceased, but the appropriateness of the shares of inheritance based upon the premise that the extra-marital child should naturally be one of the heirs.
In sum, by adopting the system of marriage by law based on monogamy, and on the premise that this system should be maintained, the determination of the appropriateness of the Provision which provides for the inheritance share for illegitimate child as one half that of the legitimate child as a supplementary provision, applicable in cases where gift during life, devise, or designation of shares of inheritance by the deceased does not exist, is within the scope of discretion of the legislature and in substance, does not generate the problem of unconstitutionality.

Concurring opinion of Justice Katsuya Onishi
I concur with the majority opinion that the share by statutory inheritance for an illegitimate child is not against Article 14, paragraph 1 of the Constitution as discrimination without reasonable grounds, but would like to add some reasons for it.
1 I agree with the majority opinion in that insofar as the Civil Code has adopted the system of marriage by law, it is inevitable that in rules concerning the establishment of parental relations and inheritance there are some difference between legitimate and illegitimate children. I also agree that the reason of enactment of the Provision which protects the legitimate marital relations and the family which was formed on the basis of this relation, and at the same time, intends to protect illegitimate children has reasonable grounds.
The Provision originates from a similar provision in the Civil Code before the War and has remained in force after the 1947 amendments. Under the societal conditions at those times in Japan, the Provision may have had some rationale.
2. However, since then, the social environment and the perception of the people have significantly changed.
Firstly, in the past, the estate in most cases comprised assets as means of living of the descendants, but today, when inheritance of business has become exceptional, such a meaning is about to lose effect, and it is now evident that as the meaning of family assets changes, changes can be seen in the perception of the people on the grounds (raison d' etre) of inheritance. The increasing of the share of inheritance in 1980 was in line with these changes.
Concerning the family, while several generations of people living together was the rule in the past, now, the number of children has become smaller, the age of the people in society has risen, and furthermore, the number of people who choose to stay single has increased. Some people point out that concerning marriage, common law marriage and those who prefer not to marry are on the increase.
In this way, the perception of the people concerning inheritance as well as marriage, parental relations and forms of the family have changed enormously and still continues to change.
3. Changes in the international environment surrounding Japan cannot be overlooked either.
Article 24 of the International Covenant on the Civil and Political Rights (Treaty No.7, 1979) provides that all children have the right to measures for the protection needed for their status as minors provided by the family, society, or the state without any discrimination by birth. Article 26 provides that the law guarantees equal and effective protection to all, against discrimination on any grounds including birth or other status. Article 2 of the Convention on the Rights of Child (Treaty No.6,1994) provides that children are guaranteed that the rights as provided by the Convention are respected and guaranteed without discrimination, regardless of the birth or other status.
Furthermore, by the 1960s, triggered by the increase in the number of illegitimate children, a majority of European countries had amended the law in order to make the share of inheritance of the illegitimate child equal to that of a legitimate child. Although there are countries in which, because of a strong tradition for the protection of the legitimate family, amendment of the law for equal treatment has yet to be adopted, there are also countries which, despite that fact that full equal treatment is not realised, equal treatment is pursued while balancing it with the rights of the spouse and legitimate children.
4. As seen above, circumstances concerning the Provision on the share of inheritance of illegitimate children have considerably changed in Japan as well as internationally, and the rationale behind the Provision which existed at the time of enactment has gradually lost validity. At this point, one cannot say that this exceeds the scope of reasonable discretion granted to the legislature, but if one limits the scope of examination to this Provision, the reasonableness as to the relationship with the reason of enactment has become significantly questionable.
5. On the other hand, Civil Law is based upon the adjustment and balancing of interests of individuals, and therefore, it is not appropriate to examine one interest separately from the other. Although provisions on inheritance do not concern pure proprietary interests as in commercial transactions, unlike mandatory provisions concerning civil status, ultimately, these are the provisions which determine to whom and how the assets of the deceased are assigned. Moreover the Provision is supplementary in that it is applicable only when there is no testament which reflects the deceased's clear intention. There are different views on the raison d'etre of inheritance, but the will of the presumed heir cannot be totally ignored. The system should be examined also from the viewpoint of how a stronger guarantee of a benefit to be granted by inheritance to one person affects the benefit the others used to have. When examining the reasonableness of the Provision, an overall consideration of the compatibility with the relevant provisions on inheritance, marriage, parental in view, including the problem of whether it is necessary to take measures to protect the interest of the spouse and others if the share of inheritance of a illegitimate child is to be made equal to that of legitimate child, is needed.
Based upon the above, while it may be appropriate to discuss the possibility of reform as a matter of legislative policy, at this moment, it cannot be concluded that the Provision is excessively unreasonable in relation to the reason of enactment.

Justice Itsuo Sonobe concurs with the concurring opinion of Justice Katsuya Onishi.

Concurring opinion of justices Hideo Chikusa and Shinichi Kawai
We concur with the majority opinion that the Provision on the share of inheritance of an illegitimate child is not against Article 14, paragraph 1 of the Constitution, but would like to add the following.
1 In general, it is possible that provision of a law had a reasonable ground at the time of enactment, but with the passing of time, circumstances involving the subject matter change and the reasonableness of the given provision becomes questionable. The normal way of dealing with such a situation is by legislative measures, such as the amendment or abolition of the provision in question or enactment of a new law. It goes without saying that this is the most desirable way of dealing with such a situation.
2. This applies to the present case as well. It is understandable that concerning the Provision, half a century after its enactment, circumstances involving illegitimate children have changed, and an opinion which, from the viewpoint of further respecting the rights of children, casts doubts on its reasonableness has emerged. However, in order to deal with such a situation, amendment of the Provision by a legislative measure is the best way.
Particularly since the Provision is an integral part of the system of inheritance and family, in order to amend it, the effect the amendment may have on related provisions and the compatibility with these provisions should be considered in the light of the entire system of inheritance and family; if necessary, other provisions should be amended or newly introduced at the same time. In addition, handling of inheritance matters based upon the Provision has been going on for many years and still continues. Presumably, preparation for the near future is being made on the same basis. Therefore, if the Provision is to be amended, the determination of the time of its taking effect and the scope of application must be examined carefully by taking into consideration the effect the change may have on the practice. All these can be achieved more properly by legislative activities of the Diet. In this way, changes in the perception of the general public can be reflected on the legislative process. It wi ll also be possible to convince them of the goal of the amendment as well as the necessity of the amendment and to make these widely known.
3. However, if the reasonableness of a particular provision of law has been lost in a significant way, and has reached the level that in the light of Article 14, paragraph 1 of the Constitution, it cannot possibly be tolerated, its application must be immediately excluded by the court declaring that the given provision is unconstitutional without waiting for legislative measures to be taken. However, in relation to this Provision, it cannot be said that it has reached such a stage.

Dissenting opinion by justices Toshijiro Nakajima, Masao Ono, Hisako Takahashi, Yukinobu Ozaki, Mitsuo Endo (Justice Ozaki gives a supplementary opinion to the dissenting opinion)
1 We are of the opinion that the qualifying proviso to the first part of Article 900, subparagraph 4 of the Civil Code (hereafter, the Provision) which determines the statutory share of inheritance of an illegitimate child to be one half that of the legitimate child is against Article 14, paragraph 1 of the Constitution and therefore is null and void, and that the original decision should be quashed.
2. (The system of Inheritance and the Criteria of Constitutionality)
Although the system of inheritance is an outcome of an overall legislative policy which has taken into consideration various social conditions and balancing of interests of the members of the family, there is a constitutional limit to legislative discretion, and it is a matter of course that it can be reviewed from the viewpoint of constitutionality.
Article 13 provides at the beginning that 'all people are respected as individuals,' and as a corollary, Article 24, paragraph 2 provides that 'on matters concerning inheritance, and family, laws should be enacted upon the basis of the dignity of individuals and the essential equality of men and women.' This should be fully respected when examining the constitutionality of a law related to family, including inheritance.
The fact that Article 14, paragraph 1 of the Constitution provides that 'all people are equal under law, and shall not be discriminated against on the ground of race, creed, sex, social status or social origin, in political, social or economic relations' is understood to mean that in the light of the dignity of individuals which is a fundamental idea of democracy, discriminative treatment against it should be eliminated. This provision does not prohibit all discrimination; it allows differentiation based upon a reasonable ground in accordance with the nature of the matter. What is reasonable should be examined in the light of the nature of the matter. In the present case, what is at issue is the constitutionality of determining the statutory share of an illegitimate child to be one half that of the legitimate child, although they are children of the same deceased. The case does not directly involve spiritual freedom, but the determination of reasonableness of discrimination at issue in the Pro vision basically depends on where the emphasis should lie - whether the attribute of the illegitimate child as part of the married family or as an outsider should be stressed, or the equal status as an individual of the illegitimate child as a child of the deceased should be stressed. Therefore, this determination shall be made in accordance not only with the existence or non-existence of reasonableness as in cases involving proprietary rights. Instead, examination of the existence of a higher level of reasonableness in relation to the reasonableness of the purpose of the law itself and its substantial relation with the means of achieving it is required. However, in this case, even the existence of simple reasonableness cannot be found.
3. (Unreasonableness of the Provision)
Concerning the reasonableness of the Provision, the majority opinion seems to presuppose that since the Civil Law adopts the system of marriage by law, the differentiation between a legitimate child born from intra-marital relations and an illegitimate child born from extra-marital relations emerges, and that there is a reasonable ground to favour the former in contrast to the latter in determining the statutory share of inheritance.
There is no disagreement as to the purpose of the law to respect marriage, but to find the differentiation in the share of statutory inheritance to be reasonable means that the emphasis is laid on the attribute of the illegitimate child that he or she is not part of the married family and the differentiation is justified by this fact. This is not compatible with Article 24, paragraph 2 of the Constitution, which provides that the respect for individual should be the basis of legislation in inheritance, as mentioned above. While it is the deceased who is responsible for the birth of an illegitimate child, the child has no responsibility, and his or her status cannot be altered by their intention or efforts. Discriminating by law against an illegitimate child, who is by no means responsible for the birth, on the ground of birth is in excess of the purpose of legislation, i.e. the respect for and protection of marriage; there is no substantial relationship between the purpose of the law and the mea ns of achieving it, and therefore, it cannot be found to be reasonable.
The majority view that the purpose of the enactment of the Provision is to protect the interest of illegitimate children and that it thus has a reasonable basis does not coincide with the real effect the Provision has on society. The Provision is part of the Civil Code which is the fundamental law on individuals' life and family relations, and although it is not mandatory, it has a normative force and should be understood to reflect the basic idea of the law on illegitimate children. Even considering the fact that the Provision concerns the area of inheritance, the fact that the share of statutory inheritance of an illegitimate child is set at one-half that of the legitimate child is one of the significant causes creating the perception in the society that illegitimate children are inferior to legitimate children. If the purpose of the legislation of the Provision is to protect illegitimate children, although it may have been compatible with the environment in the society at the time of enactmen t, at least it is not compatible to the present state of the society, and lacks reasonableness.
4. (Changes in the legislation on illegitimate children, adoption of treaties, and the unreasonableness in the contemporary period)
It is naturally possible that a law the purpose of which was regarded as reasonable and its purpose and means compatible at the time of enactment, later, with the changes in the perception of society, general trends of legislation in foreign countries, developments in legislative reforms within Japan, and ratification of treaties, now has come to be regarded as having lost the reasonableness of its legislative purpose and the compatibility of the purpose with the means. In order to determine its constitutionality, together with the purpose of legislation at the time of enactment, changes in the facts which serve as the basis of legislation as well as the content of the treaties subsequently ratified should be taken into account.
Although there was some opposition to this Provision at the time of its enactment, as indicated by the majority opinion, the purpose of the legislation was to protect marriage. At that time, it was common in other countries to differentiate between illegitimate children and legitimate children in inheritance by law. However, since then, particularly since the 1960s, the general trend of legislation in foreign countries has been to amend the law and to treat them in an equal way in the legal system including inheritance on the ground that differentiating between legitimate and illegitimate children is unreasonable.
Also in Japan, the Office of Counsellors of the Civil Law Bureau of the Ministry of Justice, based upon the discussion at the sub-committee on family law of the Civil Law Committee of the Legislative Advisory Council, published a tentative draft of a reform programme which included an amendment to the effect that the share of illegitimate children be made equal to that of legitimate children, since the Provision was questionable in the light of the idea of equality under law. This was not transformed into a bill, but at present, another draft programme of reform with a similar content has been published and the legislative activities are continuing.
Concerning international treaties, Article 26 of the International Covenant on the Civil and Political Rights which Japan ratified in 1979, provides that all people are equal under law, and enjoy the right to equal protection without any discrimination. For this goal, the law prohibits all kinds of discrimination, and guarantees equal and effective protection to all, against discrimination on any grounds including birth or other status.' Article 2, paragraph 1 of the Convention on the Rights of the Child, which Japan ratified in 1994, provides that the signatory countries shall respect and ensure that all children within their jurisdiction the rights provided by the Treaty regardless of the birth or other status of the children, their parents or statutory guardians.'
Considering the above-mentioned facts and the effect on the society which the Provision seemingly has, as well as other factors, at least at present, discriminating against illegitimate children in relation to inheritance for the purpose of respecting and protecting marriage is against the principles of the respect of individuals and their equality, lacks a substantial relationship between the purpose of legislation and means of achieving it. It is strongly questionable whether the Provision can be considered to be constitutional.
5 (Non-retrospective effect of the judgment of unconstitutionality)
Finally, it should be added that if the Provision is to be found unconstitutional, the effect of the judgment does not automatically have a retrospective effect. The Supreme Court, when deciding that a law is against the Constitution, may limit the effect of the judgment to the time after the judgment has been rendered by declaring that the judgment has no retrospective effect in cases where judgments had been rendered in the past on the premise that the given law was constitutional and valid, many people effected juristic acts on the basis of this law, there is an established relation of rights and duties, and therefore, overturning all these will harm legal stability in a significant way. We are convinced that the Provision is unconstitutional, but by expressly declaring that the effect of the decision does not have a retrospective effect on the reasons for the decision, we should maintain the validity of the judgments and agreements which presupposed the validity of this Provision.

Supplementary dissenting opinion of Justice Yukinobu Ozaki
The reason why the Provision is unconstitutional is presented in the dissenting opinion. I believe the unconstitutionality of the Provision will become even clearer by adding the following points.
1 Equality under law forms the basis of a democratic society and must be respected to a maximum extent; discrimination without reasonable grounds is prohibited by the Constitution (Article 14, paragraph 1). The Provision determines the share of statutory inheritance of an illegitimate child at one-half that of a legitimate child and thus differentiates between legitimate and illegitimate children. As the dissenting opinion pointed out, whether this is a reasonable discrimination allowed by Article 14, paragraph 1 of the Constitution or not should not be judged by the existence or non-existence of a simple reasonableness, but of a reasonableness of a higher level in the purpose of legislation and the substantial relationship between the purpose and the means of achieving it should be examined. For such examination, the level of reasonableness or necessity of the purpose of legislation itself on the one hand, and the nature, content, and extent of the rights or legal value which is to be restrained by discrimination on the other hand, should be fully considered, and whether there is a substantial link between them both should be determined.
2. The Constitution provides for marriage, but it is silent on what should be regarded as marriage. It is reasonable for the Civil Law to have selected marriage by law from among various forms of marriage. However, in relation to the purpose of legislation, among various factors which are related to marriage by law, factors which are necessary and indispensable should be differentiated from those which are not. For those which are highly necessary, it may be allowed to restrict other values protected by the Constitution. Prohibition of bigamy is an example. However, for those which are not of high necessity, other values should have preference and restriction should not be allowed.
The Provision is a supplementary provision which determines the way the estate should be divided when there is no testament. It is indeed a natural feeling of a person to leave the assets which are the fruit of his or her life to persons whom he or she loves, such as the spouse or children after the death by his or her own choice. The Civil Law respects the will of the deceased and leaves the distribution of the estate to the will of the deceased (the system of reserved share was introduced out of a different legislative consideration and will be discussed later). It is clear from the above that the Civil Law did not recognise the necessity of imposing a certain policy from the viewpoint of marriage by law on the distribution of the estate. To whom and how the estate should be distributed is related to the protection of marriage by law and the married family, but are not necessary and indispensable to them. Otherwise, the Civil Law would naturally have introduced mandatory provisions on this m atter. Thus, the very fact that the Provision is supplementary suggests that the problem of the protection of marriage by law and the married family and the provision on the share of inheritance have no direct connection. It is difficult to find that discrimination between legitimate and illegitimate children is necessary in the light of the purpose of the enactment of the Provision, and even if there is any connection, its level is minimal.
3. The effect of discrimination provided by the Provision should also be considered. The law explicitly provides that one has only half of the right which the other has, although they are children of the same person. The only reason is because the child was born between a couple who were not married. Historically, illegitimate children had been treated as inferior, but once the system of marriage by law was adopted, they were treated as persons in the shadow and despised even more. Indeed, it is often reported that they are discriminated against in an impermissible way in entering schools, finding jobs and marriage. The original purpose of the enactment of the Provision was of course not intended to have such unjustifiable results, but still in our country, there is a strong feeling that illegitimate children are inferior. The Provision is in line with this trend, but also is used as the basis of its justification.
The significance of the effect such a discriminatory trend has on the personal development of illegitimate children is obvious. The society which we endeavour to develop is a society in which people are respected as individuals and make the effort to perfect their personality based upon the right of self-determination, and are able to develop their talent to the maximum. If one is treated as a person without full personality, a person in the shadow of society from youth upwards, is it possible to develop a full and happy personality? At least, it is a major hindrance to such development. A better society cannot be attained unless constant efforts are made to eliminate such negative aspects of the society. If the Constitution declares respect for individuals and provides for equality under law, and at the same time, facilitates discriminatory treatment which has a negative influence on the spiritual development of illegitimate children and continues to retain the provision which may serve as a j ustification of such treatment, it is an enormous contradiction.
Although there may be some benefits in the means of discrimination which the Provision set out in order to protect the system of marriage by law and the married family, it results in obstruction to a person's spiritual life. They do not bestow protection by harming fundamental and important interest of a modern society. Considering the fact that the Civil Law itself evidently takes the position that matters which scarcely involve public interest can be left to the party, this conclusion is inevitable.
4. The interest which the married family has in relation to the estate is said to be greater than that of a illegitimate child. Usually, it is argued that the family of the legitimate child has led a family life longer and thus, the affection is deeper, and has contributed more to the accumulation of the estate, and therefore, it is natural that the share of inheritance should be larger. However, each family relation is different, and it is extremely questionable whether one should rely on such a generalisation, and as a result, infringes the basic rights of others. I would dare to point out that cases where illegitimate relations emerge may be an exceptional situation to the general view. If, conceding to such generalisation, the share of inheritance of the married family should be made larger, there is a means to achieve that purpose without infringing other person's rights and casting doubts on constitutionality. It is sufficient to use the testament.
Basically, disposal of the inheritance estate is left to the will of the deceased and even if it is disposed in a way which is against the expectation of the family of the deceased, no one can object. This is the same with the gift during life. What is decisive in the end is the will of the deceased and whether the family was linked by affection which genuinely deserves such treatment. This is the essence of inheritance, and provisions on the statutory share of inheritance are merely a means of convenience. At the time of enactment, when sufficient attention was not paid to fundamental human rights, the Provision was accepted without any serious doubt. If one considers without prejudice the fact that the Provision unreasonably discriminates against illegitimate children and the seriousness of the harm resulting from this discrimination, and, at the same time, takes into account that the benefit which is to be gained by the Provision is not related to public interest, but is of the nature which can be determined by the will of the party alone, one cannot but deny the validity of the Provision which is a cause of increasing the handicap of illegitimate children.
5. For the democratic society which we pursue, equality under law is a significant basis. Since the purpose of enactment of the Provision has little reasonableness or necessity, the resulting sacrifice is significant. Furthermore, even without the Provision, there is a means to attain the result which is suitable for specific circumstances. It is totally impossible to acknowledge substantial relationship between the purpose of enactment of the Provision and discrimination against illegitimate children. The Provision which compels a meaningless sacrifice should be regarded as being unconstitutional.

Justice Ryohachi Kusaba
Justice Seiichi Ohori
Justice Itsuo Sonobe
Justice Toshijiro Nakajima
Justice Tsuneo Kabe
Justice Katsuya Onishi
Justice Motoo Ono
Justice Toru Miyoshi
Justice Masao Ono
Justice Hideo Chikusa
Justice Shigeharu Negishi
Justice Hisako Takahashi
Justice Yukinobu Ozaki
Justice Shinichi Kawai
Justice Mitsuo Endo