Does an adult child whose surname and origin were changed to the mother's under Article 781(6) of the Civil Act automatically become a member of the mother's jongchung? Supreme Court Decision 2017Da260940 on sharing the common ancestor's surname and origin

Question

Article 781 of the Civil Act provides that a child takes the father's surname and origin, unless the parents agreed at the time of the marriage registration that the child would take the mother's (paragraph 1), and that where a change of the child's surname and origin is necessary for the child's welfare, they may be changed, with the court's permission, on the application of the father, the mother or the child (paragraph 6). A jongchung is a grouping formed around a common ancestor. The question is whether an adult child whose surname and origin were changed to the mother's under Article 781(6), and who thus shares the surname and origin of the common ancestor of the jongchung the mother belongs to, becomes a member of that jongchung as a matter of course.

Decision 2017Da260940 addresses that question in an action for confirmation of member status. The plaintiff, whose birth was registered under the father's surname and origin, obtained permission from the Seoul Family Court on 23 June 2014 to change to the mother's surname and origin, and registered the change on 15 July 2014. On 7 November 2015 the mother asked the defendant jongchung to recognise the plaintiff's membership; after the jongchung resolved on 9 January 2016 not to recognise it, the plaintiff sued. The Supreme Court dismissed the jongchung's appeal.

Material to check

The statutes are Article 781 of the Civil Act, on a child's surname and origin, including paragraph 1 on the father's surname and origin and on the parents' agreement that the child take the mother's, and paragraph 6 on a change permitted by the court for the child's welfare; Article 1, under which civil matters not provided for in statutes are governed by customary law and, failing that, by reason; Article 31, under which a corporation can be formed only in accordance with statutory provisions; and Article 106, under which, where a custom differs from a statutory provision unrelated to good morals or social order, the custom applies if the parties' intention is unclear.

The decisions are Decision 2017Da260940 and Decision 2002Da1178 (21 July 2005, en banc), which it cites. Decision 2002Da1178 set out the meaning and effect of customary law and when a norm created by repeated social practice loses its legal effect. It held ineffective the customary rule limiting jongchung membership to adult men, and held that descendants sharing the common ancestor's surname and origin become members as a matter of course on reaching majority, without distinction of sex. It applied this changed view only to membership and legal relations arising after that judgment, but made an exception for the claim for confirmation of member status then pending before it.

Possible readings

When the decision is read with Decision 2002Da1178, membership of a jongchung follows from the jongchung's purpose and essence. A jongchung is a spontaneous kinship grouping formed to guard the common ancestor's tombs, hold rites and foster fellowship among members; on that basis a descendant who shares the common ancestor's surname and origin becomes a member as a matter of course on reaching majority, without distinction of sex. A customary rule confining membership to adult men has lost its legal effect because it no longer accords with the changed legal order founded on the Constitution, and by the same reasoning a custom that excludes an adult woman's descendants solely because they are maternal relatives can hardly be regarded as still effective customary law.

Article 781 supplies a second ground. The Court reasoned that, because a child who takes the mother's surname and origin from birth under the proviso to Article 781(1) becomes a member of the jongchung to which the mother belongs, there is no rational reason to treat differently a child whose surname and origin were changed to the mother's after birth with the court's permission under Article 781(6). It referred to the constitutional guarantees of equality before the law and of marriage and family life founded on individual dignity and the equality of the sexes, and relied on the Civil Act amendments of 13 January 1990, which defined the range of relatives without discriminating between paternal and maternal relatives, and of 31 March 2005, which abolished the head-of-family system and introduced Article 781(6).

A third point follows from the changed surname and origin itself. Once a child's surname and origin have been changed to the mother's with the court's permission, the child no longer follows the father's and so leaves the jongchung to which the father belongs; since a person cannot belong to several jongchung at once, denying the child membership of the mother's jongchung would strip the child of membership altogether and offend the constitutional principle of equality. The Court added that the jongchung's own bylaws define membership by 'adult men and women who are blood relatives' without distinguishing paternal and maternal lines, and that membership changes, such as an adopted child joining the adoptive father's jongchung, were allowed even under the former customary law, so this result is not an artificial alteration of membership.

What the decisions held

Decision 2017Da260940 (26 May 2022) dismissed the defendant jongchung's appeal and ordered it to bear the costs of appeal, on the ground that an adult child whose surname and origin have been changed to the mother's under Article 781(6) becomes a member of the jongchung to which the mother belongs as a matter of course, as a descendant sharing the surname and origin of that jongchung's common ancestor. The reporting Justice was Justice Park Jeong-hwa, and the four-Justice bench decided unanimously.

On the facts taken from the court below and the record, the plaintiff was registered at birth under the father's surname and origin; applied to the Seoul Family Court on 6 December 2013 (case 2013Neu-Dan30408) for permission to change surname and origin; obtained permission on 23 June 2014 to change to the mother's surname and origin; and registered the change on 15 July 2014. On 7 November 2015 the mother asked the defendant to recognise the plaintiff's membership, but on 9 January 2016 the defendant resolved at an executive meeting not to recognise it.

The Court held the plaintiff to be a member of the defendant jongchung and found an interest in confirmation because the defendant disputed that status. It upheld the Seoul High Court's judgment of 25 August 2017 (2017Na2015421), which had allowed the plaintiff's claim, holding that the court below had not misunderstood the law on matters such as the constitutional right to pursue happiness, freedom of association, customary law on member status, or the principle, in the main text of Article 781(1), that a child takes the father's surname and origin.

Points left open

The decision does not settle the temporal scope of membership. Decision 2002Da1178 stated that its changed view applies only to member status and legal relations newly arising after that judgment, while making an exception for the claim for confirmation of member status then before it. The texts read for this brief do not set out the full reasons for that exception, and Decision 2017Da260940 does not address how far the changed view extends to a jongchung's past legal relations.

The decision also leaves open cases with different facts. It turned in part on the defendant's bylaws, which define membership by adult male and female blood relatives without dividing paternal and maternal lines, so it does not answer whether a case involving a jongchung with differently drafted bylaws, or a dispute over whether a claimant descends from the three brothers named in such bylaws, would be resolved the same way. Nor did the Court revisit the separate opinion recorded in Decision 2002Da1178, which would have admitted an adult woman on her expression of intent to join rather than automatically; the majority held that membership arises regardless of the person's intention.

When to reconsider

We will revisit this brief if Article 781 of the Civil Act is amended, if a later Supreme Court decision addresses jongchung bylaws that limit membership differently, or if the reasons given in Decision 2002Da1178 on the temporal effect of the changed view on membership are applied to a claim other than one for confirmation of member status.

Statutes referred to

• 민법 제1조, 제31조, 제106조, 제781조
• 헌법 제11조, 제36조

Decisions referred to

• 대법원 2022. 5. 26. 선고 2017다260940 판결 · Decision ledger
• 대법원 2005. 7. 21. 선고 2002다1178 전원합의체 판결

Verification status

The texts read for this brief were the current text of Civil Act Articles 1, 31, 106 and 781 and the published holdings, summary and reasons of Decision 2017Da260940 and of Decision 2002Da1178 (21 July 2005, en banc), all read at the National Law Information Center on 24 October 2026. Decision 2017Da260940 applies Article 781(1) and (6) of the Civil Act.