On March 25, 2026, Japan’s Supreme Court decided that the six nationwide “Freedom to Marry for All” lawsuits would be heard by its 15-member Grand Bench. The central issue is whether provisions of the Civil Code and Family Register Act that prevent same-sex couples from marrying comply with the Constitution. The ruling is expected in 2027.
The six cases were filed in Sapporo, Tokyo in two separate actions, Nagoya, Osaka and Fukuoka. The plaintiffs argue that excluding same-sex couples from the marriage system violates constitutional protections and have sought damages from the state. The Sapporo District Court issued the first ruling in March 2021, finding the exclusion unconstitutional under Article 14(1). Subsequent district courts reached differing conclusions while recognizing the need for legal protection for same-sex couples.
At the appellate level, the Sapporo, first Tokyo, Nagoya, Osaka and Fukuoka high courts all found constitutional problems with excluding same-sex couples from marriage. In March 2024, the Sapporo High Court went further, holding that a separate partnership framework would not provide an equivalent substitute for marriage itself.
The Tokyo High Court reached a different conclusion on November 28, 2025, ruling that the current system does not violate Articles 14(1) or 24 of the Constitution. It became the only appellate court among the six cases to uphold the constitutionality of the existing framework. The court held that constitutionally protected “marriage” does not encompass same-sex couples and that the design of family-related legislation remains within the Diet’s discretion.
The ruling also placed emphasis on the procreative potential of opposite-sex couples and the role of reproduction in the family system. The source analysis challenges that reasoning from a family-law perspective, pointing to developments in assisted reproduction, adoption and diverse family structures as factors that complicate a purely biological approach to defining marriage.
The Grand Bench will consider whether same-sex marriage falls within constitutional protection, whether the current system creates an unjustified distinction, and how much legislative discretion the Diet should retain in designing family law. Its decision could affect marriage registration, family status, inheritance and other legal protections connected to spousal status.
No specific judgment date has been announced. The transfer to the Grand Bench places Japan’s constitutional dispute over same-sex marriage before the country’s highest court, while any subsequent legislative response by the Diet will remain a separate issue.
Asian Editorial Department: Kim Min-jun