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民法 (Civil Code) arts. 818 + 819 + 824-2 — Joint custody + alternation framework (verbatim, 2024 reform)

Jurisdiction: Japan · Citation: 民法 (Minpō — Civil Code) arts. 818, 819, 824-2 (as amended by Reiwa 6 Law No. 33 of 2024) · Authoritative source: e-Gov 法令検索 — 民法

The historic 2024 reform of Japanese family law. Reiwa 6 Law No. 33 (2024) abolished the post-divorce sole-custody framework that had governed Japan since 1898 — replacing it with a joint-custody-or-sole-custody framework where the court may order 共同親権 (kyōdō shinken — joint parental authority) over the parents' objections. The reform takes effect 2026-04-01. The provisions are the structural Japanese parallel to: - Korea Civil Act arts. 909-913 (joint custody post 2007 reform) - Germany BGB §§ 1626 + 1671 (gemeinsame elterliche Sorge) - France CC arts. 372-373 (autorité parentale conjointe) - Italy CC art. 337-ter (affidamento condiviso)

Japan is doctrinally distinctive globally because the 2024 reform abolished a 126-year sole-custody tradition under direct pressure from international PA-recognition discourse and ECHR-equivalent jurisprudence on parental rights. Japan had been the major industrialized outlier maintaining post-divorce sole custody — the 2024 reform brings Japanese family law into structural alignment with the EU/US/CommonLaw shared-custody majority.

Verbatim text (current consolidated, post-Reiwa 6 Law No. 33)

Art. 818 民法 — 親権者

成年に達しない子は、父母の親権に服する。

子が養子であるときは、養親の親権に服する。

親権は、父母の婚姻中は、父母が共同して行う。ただし、父母の一方が親権を行うことができないときは、他の一方が行う。

Art. 819 民法 — 離婚又は認知の場合の親権者

父母が協議上の離婚をするときは、その協議で、父母の双方又は一方を親権者と定めなければならない。

裁判上の離婚の場合には、裁判所は、父母の双方又は一方を親権者と定める。

子の出生前に父母が離婚した場合には、親権は、母が行う。ただし、子の出生後に、父母の協議で、父を親権者と定めることができる。

父が認知した子に対する親権は、父母の協議で父と母の双方又は一方を親権者と定めたときに限り、父が行う。

第一項、第三項又は前項の協議が調わないとき、又は協議をすることができないときは、家庭裁判所は、父又は母の請求によって、協議に代わる審判をすることができる。

子の利益のため必要があると認めるときは、家庭裁判所は、子の親族の請求によって、親権者を他の一方に変更することができる。

Art. 824-2 民法 — 親権の行使方法 (post 2024 reform)

親権を行う父母は、共同してこれを行う。ただし、次に掲げる場合には、その一方が行うことができる。

一 他の一方が親権を行うことができないとき。

二 子の利益のため急迫の事情があるとき。

三 監護及び教育に関する日常の行為をするとき。

親権を行う父母の意見が一致しないときは、家庭裁判所は、父又は母の請求によって、親権の行使について必要な事項を定めることができる。

English working translation

Art. 818 — Persons exercising parental authority

A child who has not attained the age of majority is subject to the parental authority of his/her father and mother.

Where the child is an adopted child, he/she is subject to the parental authority of the adoptive parents.

Parental authority is, during the marriage of the father and mother, exercised jointly by the father and mother. Where, however, one of the parents cannot exercise parental authority, the other exercises it.

Art. 819 — Persons exercising parental authority in case of divorce or recognition

When the father and mother divorce by agreement, they must determine, by their agreement, that both or one of them is the person exercising parental authority.

In case of judicial divorce, the court determines that both or one of them is the person exercising parental authority.

Where the father and mother divorce before the birth of the child, parental authority is exercised by the mother. Provided, however, that after the birth of the child, the parents may, by agreement, designate the father as the person exercising parental authority.

[Provisions on recognized children]

Where the agreement under paragraphs 1, 3, or the preceding paragraph cannot be reached or cannot be made, the Family Court may, upon application of the father or mother, make an adjudication in lieu of the agreement.

Where it finds it necessary for the welfare of the child, the Family Court may, upon application of the child's relatives, change the person exercising parental authority to the other parent.

Art. 824-2 — Method of exercise of parental authority (post-2024)

The father and mother who exercise parental authority exercise it jointly (共同してこれを行う). Provided, however, that in the following cases, one of them may exercise it:

  1. Where the other cannot exercise parental authority;

  2. Where there are urgent circumstances (急迫の事情) for the welfare of the child;

  3. When making acts of daily monitoring and education (監護及び教育に関する日常の行為).

Where the opinions of the father and mother exercising parental authority do not coincide, the Family Court may, upon application of the father or mother, determine the necessary matters concerning the exercise of parental authority.

Why this matters for PA

  • The historic shift from sole to joint custody (art. 819 + 824-2). Before the 2024 reform, art. 819 required that one parent be designated sole custodian post-divorce — Japan was the major industrialized outlier on this. The 2024 reform replaced the one-of-them mandatory framework with a both-or-one framework, expressly authorizing joint custody (共同親権 kyōdō shinken). In PA-pattern cases this is structurally transformative: the alienating parent's previous near-monopoly on post-divorce custody is no longer guaranteed.
  • The court's adjudication-in-lieu power (art. 819 paragraph 5). Where parents cannot reach agreement, the Family Court may make an adjudication in lieu of the agreement. This is doctrinally important because it provides structural pathway for joint custody where the alienating parent refuses agreement.
  • The change-of-custodian power (art. 819 paragraph 6). Where it finds it necessary for the welfare of the child, the Family Court may change the person exercising parental authority to the other parent. The change-of-custodian provision applies regardless of whether the original allocation was joint or sole. In PA-pattern cases this provides the structural transfer remedy.
  • The relatives' standing (art. 819 paragraph 6). Upon application of the child's relatives. Doctrinally distinctive — the change-of-custodian application can be brought by the child's relatives, not only the targeted parent. This provides structural pathway for grandparents or other family members to seek intervention where the targeted parent is unable to litigate effectively.
  • The joint-exercise default (art. 824-2 first paragraph). 親権を行う父母は、共同してこれを行う. The parents exercising parental authority exercise it jointly. This is the structural starting point post-2024 reform. In PA-pattern cases this means the alienating parent's unilateral decisions on enumerated matters are not lawfully authorized — joint exercise is the default.
  • The three exceptions (art. 824-2 first paragraph exceptions). Joint exercise admits three exceptions:
  • When the other cannot exercise (incapacity)
  • 急迫の事情 (urgent circumstances) for the child's welfare
  • 監護及び教育に関する日常の行為 (acts of daily monitoring and education)
  • The 急迫の事情 exception is the structural emergency provision; the 日常の行為 exception preserves day-to-day decision-making by the cohabiting parent. In PA-pattern cases the 急迫の事情 exception requires evidenced urgency — alienating-parent invocation of this exception for non-urgent matters constitutes overreach.
  • The Family Court adjudication power for disagreement (art. 824-2 second paragraph). 父又は母の請求によって、親権の行使について必要な事項を定めることができる. Upon application of the father or mother, the Family Court may determine the necessary matters concerning the exercise of parental authority. This is doctrinally distinctive — the court is the structural arbiter of disagreements, not the parties unilaterally. In PA-pattern cases this provides express pathway for the targeted parent to invoke court adjudication where the alienating parent refuses joint exercise.
  • The pre-birth divorce framework (art. 819 paragraph 3). 父母が離婚した場合には、親権は、母が行う. Pre-birth divorce produces maternal custody by default. This is doctrinally significant in PA-pattern cases where pre-natal separation occurred — but the 父母の協議で、父を親権者と定めることができる (father may be designated by parental agreement post-birth) provision preserves structural flexibility.
  • The international PA-discourse context. The 2024 reform was driven by sustained international pressure including:
  • The European Parliament resolution of 2020-07-08 on the international and domestic parental abduction of EU children in Japan
  • The French Senate resolution of 2020-02-05
  • Sustained ECHR jurisprudence on parental rights
  • Domestic kobetsu mondai (kidnapping problem) advocacy by left-behind parents
  • The 2024 reform's preparatory documents expressly acknowledged the PA-discourse context, providing operational interpretive guidance for treating PA-pattern conduct as engaging the welfare-protective framework.
  • The transitional implementation issues. The reform's 2026-04-01 effective date creates significant transitional questions about:
  • Pre-reform sole-custody arrangements (whether and how they can be revised)
  • Cross-border PA-pattern cases (Hague 1980 + Japan's particular jurisprudence)
  • Family-court capacity to absorb the new caseload
  • Japanese family-court practice is expected to continue developing through 2026-2028 as the reform's operational framework consolidates.

Procedural application

  • The competent court is the 家庭裁判所 (Kateisaibansho — Family Court) under 家事事件手続法 (Domestic Relations Case Procedure Act 2011)
  • 家庭裁判所調査官 (Family Court Probation Officer) provides welfare assessment
  • The child is heard under the 家事事件手続法 art. 65 + art. 152 — capacity-based standard, typically age 10+ for direct hearing
  • 家事調停 (family mediation) is structurally available and frequently engaged pre-adjudication
  • Appellate review to the 高等裁判所 (High Court) + cassation to the 最高裁判所 (Supreme Court)

Use in alienating-conduct cases

  • The pre-reform sole-custody framework had been structurally incompatible with PA-protection — the alienating parent's monopoly on post-divorce custody was near-total
  • The 2024 reform's joint-custody framework provides structural transformation, but operational practice will develop through 2026-2028
  • The Saikō saibansho (Supreme Court) is expected to develop the 子の利益 (child's welfare) + kyōdō shinken framework in PA-pattern cases
  • Where alienating conduct is established post-reform, Japanese courts may:
  • First-tier: order 家事調停 (mediation) under DRCPA
  • Second-tier: fix specific 共同親権 arrangements under art. 819
  • Third-tier: order change-of-custodian under art. 819 paragraph 6
  • Apex-tier: 親権喪失 (loss of parental authority) under art. 834
  • The 面会交流 (menkai kōryū — contact/visitation) framework operates alongside the parental-authority provisions, with structural enforcement via 履行勧告 (rikō kankoku — performance encouragement) and 間接強制 (kansetsu kyōsei — indirect compulsion)

Cross-reference