The Normative Force of Customary Law and Constitutional Equality: Standards from Three Supreme Court Judgments

Question

Where no consultation has taken place among the co-heirs of the deceased to determine the officiant of the ancestral rites, does a custom of giving priority to the eldest son by distinguishing gender and status as children born in or out of wedlock still possess legal normative force today? The Supreme Court found that this custom, lacking any reasonable ground for discrimination on the basis of gender, runs contrary to the spirit of Article 11, paragraph (1) and Article 36, paragraph (1) of the Constitution, and changed the criterion for determination. The new criterion provides that, absent consultation and in the absence of special circumstances, the eldest among the nearest lineal descendants, without distinction as to gender or as to children born in or out of wedlock, is regarded as the officiant of the ancestral rites.

Where ownership of land and the building thereon, formerly held by the same person, has been divided through sale or the like, and there is no special stipulation for demolition, is the customary law that the building owner acquires statutory superficies still maintained today? One interpretation holds that land and building are separate immovables and that the need to prevent loss from demolition warrants retaining customary law as a supplementary device, while another interpretation contends that its effect must be narrowed in light of the principle of numerus clausus of real rights. The crux is whether the continued existence of customary law should be judged by whether social and legal conviction has disappeared and whether practice has undergone an essential change.

Where an adult who has changed their surname and given name to those of their mother with the court's permission is a descendant of a common ancestor, do they become an ex officio member of that jongdong clan association? At issue is whether the criterion for membership in the clan association is identity of surname and given name without distinction of gender, or whether it should be based on the birth relationship existing before the change of surname and given name. This question is bound up with how the abolition of the family headship system (hojuje) and the constitutional principle of equality are to be reflected in the interpretation of customary law.

Material to check

First, the original texts of the three judgments and their statements of facts must be read precisely. Supreme Court Decision 2018Da248626 is a case that reassessed the legal principle of eldest-son priority, drawn from an earlier en banc judgment, in a dispute over the status of the officiant of the ancestral rites; Supreme Court Decision 2017Da236749 is a case that recognized the legal normative force of the customary law of statutory superficies; and Supreme Court Decision 2017Da260940 is a case addressing the change of surname and given name and membership in a clan association. It is necessary to read each judgment by distinguishing which issues it took as the object of its holding and which portions it left as incidental explanation.

Cross-check the current wording of the cited provisions at the Korea Law Information Center. Confirm what role Civil Act Article 1, Article 31, Article 106, Article 185, Article 280, paragraph (1), subparagraphs 1 and 2, Article 281, paragraph (1), Article 305, Article 366, Article 781, paragraphs (1) and (6), Article 877, and Article 1008-3 play with respect to the supplementary application of customary law and relations of real rights, family, and succession. In particular, the wording of Article 185 of the Civil Act serves as the starting point for determining what the basis is for the creation of real rights under customary law.

The constitutional provisions and the definitional provisions of the relevant statutes must also be checked together. Examine what basis was drawn upon from the principle of equality under Article 11, paragraph (1) of the Constitution and the provisions on marriage and family life under Article 36, paragraph (1) in judging the legal normative force of customary law. Article 2, subparagraph 16 of the Act on Funeral Services, Article 12, paragraph (3) of the Organs Transplant Act, Article 16, paragraph (2), subparagraph 2 of the Bioethics and Safety Act, and Article 16, paragraph (4), subparagraph 2 of the Act on the Safety of and Support for Advanced Regenerative Medicine and Advanced Biological Products are materials through which changes in legal concepts surrounding the living body and the dead body may be glimpsed. Article 6 of the Act on Standing Trees and Article 10 of the Provisional Registration Security Act serve as subjects of comparison as special rules on real rights in immovables.

Finally, factual materials supporting the continued existence of the custom itself must be assembled. Materials concerning whether the shape of family ancestral rites and funerals has changed, whether the social functions of grave maintenance and ancestral rites have shifted toward commemoration, to what extent special stipulations for demolition prevail in real estate transaction practice, and how much distinction of gender remains in the composition and operating practices of clan associations become the grounds for judging the legal conviction and practice underlying customary law. Portions where materials are insufficient must be left as limits of the determination.

Possible readings

The first interpretation emphasizes the stability of customary law. The customary law of statutory superficies is rooted in the legal conviction of society as contemplated by Civil Act Article 185, and since the need to prevent loss from demolition remains alive today, the customary law retains its legal normative force. Likewise, since the order of family ancestral rites and clan associations rests on long-standing practice, adjusting by relaxing existing standards rather than hastily abolishing them preserves predictability. From this vantage point, the constitutional principle of equality is likewise viewed not as invalidating custom but as a standard indicating the direction of interpretation.

The opposing interpretation emphasizes the supremacy of the Constitution. A custom that divides the qualifications for officiant of the ancestral rites and for membership in a clan association along gender lines is discrimination without reasonable ground, and the law's maintenance of such a custom as a legal norm runs contrary to Article 11, paragraph (1) and Article 36, paragraph (1) of the Constitution. Customary law loses its effect whenever legal conviction disappears, so once society has accepted gender equality as legal conviction, customs of eldest-son priority or male primacy can no longer be recognized by law. From this vantage point, the realization of equality takes precedence over the stability of customary law.

The third interpretation reconciles the two principles. The effect of customary law is recognized in principle, while only the core portions running afoul of the constitutional principle of equality are removed and the remaining structure is preserved. In the officiant-of-ancestral-rites case, only eldest-son priority was discarded and a new standard of the eldest among the nearest lineal descendants was established; in the statutory superficies case, since there is no element of gender discrimination, the existing customary law was maintained as it stood. In the clan association case, only the requirement suited to the purpose of identity of surname and given name was retained and distinction of gender was removed. From this vantage point, customary law is a supplementary means of filling gaps in statutory provisions, operating only within the limits of the Constitution.

What the decisions held

Supreme Court Decision 2018Da248626 changed the standard for determining the officiant of the ancestral rites. The majority opinion viewed the legal principle of the earlier en banc judgment—which, absent consultation, gave priority to the eldest son or eldest grandson and, in the absence of sons, to the eldest daughter—as discrimination on the basis of gender lacking reasonable ground and contrary to the spirit of the Constitution. Since the meaning of ancestral rites has shifted toward placing greater weight on commemoration than on succession of the family line, and since the form of funerals and ancestral rites has also changed, absent consultation and in the absence of special circumstances, the eldest among the nearest lineal descendants, without distinction as to gender or as to children born in or out of wedlock, becomes the officiant of the ancestral rites. The new legal principle applies to successions after its pronouncement, but in this case it was applied retroactively as an adjudicatory norm.

Supreme Court Decision 2017Da236749 held that the customary law whereby, when land formerly owned by the same person and the building thereon come to have separate owners, the building owner acquires statutory superficies absent a special stipulation for demolition of the building, continues to possess legal normative force at present. Since Civil Act Article 185 contemplates the creation of real rights under customary law, its effect cannot be denied merely as a restriction of ownership, and the need to prevent demolition loss was recognized from the fact that land and building are separate immovables. The duration follows Civil Act Article 280, paragraph (1), subparagraphs 1 and 2, and Article 281, paragraph (1), and a claim for ground rent is available, so a device protecting the land owner is provided in tandem. Since no materials showing the disappearance of legal conviction or an essential change in practice were presented, it was determined that the effect is maintained.

Supreme Court Decision 2017Da260940 regarded a jongdong clan association as a naturally arising tribal group whose purposes are the maintenance of the graves of a common ancestor, ancestral rites, and fellowship among its members. It set forth the standard that descendants sharing the same surname and given name as the common ancestor become members ex officio upon attaining majority, without distinction of gender, and explained that since the effect of the customary law confining membership to males under the earlier en banc judgment has been lost, a custom excluding persons on the ground of the maternal line cannot be regarded as law. Where the surname and given name have been changed pursuant to Civil Act Article 781, paragraph (6), the matter must also be regarded, in light of constitutional equality and the purpose of abolishing the family headship system (hojuje), as identical to the case of following the mother's surname and given name from birth. The plaintiff in this case is an adult who changed to the mother's surname and given name with the court's permission, and thus is recognized as a member of the defendant clan association.

Practical checklist

First, check whether the content of the disputed custom and the basis for its formation have been established in documents. Determine whether the custom contains elements that allocate qualification or status according to sex, legitimacy or marital status, and whether such elements are essential to the custom or merely incidental practice. If they are essential, the custom is likely to conflict with the constitutional principle of equality, so an alternative standard should be prepared in advance.

Second, confirm whether there is any agreement or arrangement between the parties. In the presider-over-ancestral-rites case and the statutory superficies case, the parties' intentions take precedence, as with an agreement on the presider over ancestral rites or a special agreement to demolish the building. Record whether any such arrangement was oral or in writing, and what its scope and conditions are.

Third, examine whether factual materials can support the proposition that the custom still commands legal conviction. In the statutory superficies case, the Court recognised the custom's effect because no materials were presented showing that the legal conviction had disappeared or that the practice had changed in substance. Conversely, in the presider-over-ancestral-rites case, the change in the social function of ancestral rites and funerals served as the ground for reassessing the custom. Set out which body of material prevails.

Fourth, check the point from which the new standard applies and the scope of its exceptions. In the presider-over-ancestral-rites case, the new legal principle applies to successions occurring after the pronouncement of the judgment, but was applied retroactively to that case as the norm of adjudication. Moreover, the principle of priority for the eldest among the nearest relatives remains subject to an exception for cases of manifest unreasonableness, so whether such exceptional circumstances exist in the case should be examined separately.

Glossary

Statutory superficies refers to the superficies acquired by the owner of a building, unless there is a special agreement to demolish the building, where land and the building on it that belonged to the same person come to have different owners. It is a mechanism recognised by customary law to prevent the loss that demolition of the building would cause, given that land and buildings are separate items of real estate; because Article 185 of the Civil Act contemplates the creation of real rights by customary law, its effect cannot be denied merely on the ground that it restricts ownership. The rules on its duration and on rent follow Article 280(1), subparagraphs 1 and 2, and Article 281(1) of the Civil Act.

A jongjung (clan) is a naturally formed kinship group constituted for the purposes of tending the graves of a common ancestor, performing ancestral rites, and fostering fellowship among its members. In light of that purpose and nature, descendants who share the surname and ancestral seat (bon) of the common ancestor automatically become members upon reaching majority, regardless of sex. Determination of membership centres on the objective criterion of identity of surname and ancestral seat, and, in keeping with the purport of constitutional equality, a change of surname and ancestral seat is treated in the same way as if the person had had them from birth.

The presider over ancestral rites refers to the person holding the status of conducting the ancestral rites for the deceased, determined first by agreement among the co-heirs. Where no agreement is reached, the principle of priority for the eldest son formerly applied, but a recent judgment held that this principle lacks any reasonable ground for its sex-based discrimination and replaced it with a standard of priority for the eldest among the nearest relatives. Customary law refers to a practice that, even without any statutory provision, has normative legal force grounded in society's conviction of its legal validity; it loses its effect where that legal conviction disappears, where the practice changes in substance, or where it ceases to conform to the legal order as a whole at the time of application.

Sources and limitations

This brief is based only on three judgments, Supreme Court 2018Da248626, Supreme Court 2017Da236749 and Supreme Court 2017Da260940, and on the provisions cited in them. The current wording of the provisions was checked against the National Law Information Center as of 15 October 2026. No cases other than the three judgments are cited, so determinations on other sets of facts fall outside the scope of this brief.

This material has been prepared for general research purposes and is not legal advice. Any determination in an individual case requires separate verification of the facts, the evidence and whether the relevant provisions have recently been amended, and, where necessary, advice should be obtained from an attorney or other professional. The interpretations and checklist questions in this brief are merely a summary intended to assist research and do not themselves produce any legal effect.

Points left open

The problem remaining behind the new standard for the officiant of the ancestral rites is the scope of cases manifestly unjust. Although the principle of priority to the eldest among the nearest lineal descendants has been declared, detailed criteria as to which circumstances are manifestly unjust are not fully set out in the judgment. Where the eldest son has long presided over the ancestral rites, where the eldest refuses to perform the rites, or where the division of property and the presiding over the rites are intertwined, at what point an exception is recognized will need to be confirmed in future cases.

With respect to the customary law of statutory superficies, the boundary between the public interest in preventing demolition and the protection of the land owner's ownership remains. The judgment pointed to the devices protecting the land owner through the rules on claims for ground rent and duration, but it is uncertain how long customary law will remain a supplementary solution, and what determination will be made if the scope of practice regarding special stipulations for demolition in real estate transaction practice changes. The baseline of the effect that a change of surname and given name has on clan membership qualifications also appears likely to be made clearer in subsequent cases.

When to reconsider

This white paper will be reviewed anew if, in a new case concerning the officiant of the ancestral rites and clan association membership, concrete criteria for cases manifestly unjust are presented, or if the scope of exceptions to the principle of priority to the eldest among the nearest lineal descendants is fixed. It is also subject to reexamination if the commentary on Article 11, paragraph (1) and Article 36, paragraph (1) of the Constitution changes, or if Civil Act Article 781, paragraph (6), Article 877, and Article 1008-3 are amended so that the relationship between a change of surname and given name and succession alters.

As to statutory superficies, the matter must be looked at again when Civil Act Article 185, Article 280, paragraph (1), subparagraphs 1 and 2, Article 281, paragraph (1), Article 305, and Article 366 are amended, or when materials emerge showing that the practice of special stipulations for demolition in real estate transaction practice has changed essentially. In addition, if the relevant provisions of the Act on Funeral Services, the Organs Transplant Act, the Bioethics and Safety Act, and the Act on the Safety of and Support for Advanced Regenerative Medicine and Advanced Biological Products are amended so that the change in legal concepts concerning the living body and the dead body becomes distinct, the legal assessment of the customs of ancestral rites and grave maintenance should also be revisited together.

Statutes referred to

• 민법 제1조, 제31조, 제106조, 제185조, 제280조 제1항 제1호, 제280조 제1항 제2호, 제281조 제1항, 제305조, 제366조, 제781조 제1항, 제781조 제6항, 제877조, 제1008조의3
• 헌법 제11조 제1항, 제36조 제1항
• 장사 등에 관한 법률 제2조 제16호
• 장기 등 이식에 관한 법률 제12조 제3항
• 생명윤리 및 안전에 관한 법률 제16조 제2항 제2호
• 첨단재생의료 및 첨단바이오의약품 안전 및 지원에 관한 법률 제16조 제4항 제2호
• 입목에 관한 법률 제6조
• 가등기담보 등에 관한 법률 제10조

Decisions referred to

• 대법원 2023. 5. 11. 선고 2018다248626 전원합의체 판결 · Decision ledger
• 대법원 2022. 7. 21. 선고 2017다236749 전원합의체 판결 · Decision ledger
• 대법원 2022. 5. 26. 선고 2017다260940 판결 · Decision ledger

Verification status

The original text of the relevant provisions and the texts of Supreme Court Decisions 2018Da248626, 2017Da236749, and 2017Da260940 were cross-checked against the Korea Law Information Center as of 2026-10-15. This white paper cites only the three judgments addressed.