Yes, cousin marriage is legal in Japan, but subject to strict familial restrictions under the Civil Code. The law permits unions between cousins unless they share a lineal ancestor within three generations, aligning with Japan’s eugenics-inspired provisions. Local Family Court approval may be required for borderline cases, reflecting 2026’s tightening oversight on consanguinity disputes.
Key Regulations for Cousin Marriage in Japan
- Article 734 of the Civil Code prohibits marriages between relatives within the third degree of kinship (e.g., first cousins, uncle-niece). This includes both direct lineal descendants and collateral relatives sharing a common ancestor.
- Article 735 allows exceptions if the couple obtains Family Court approval, typically granted only when genetic risks are deemed negligible by medical assessments. Recent 2026 amendments emphasize mandatory pre-marital genetic counseling for such cases.
- Local municipal offices enforce these rules during marriage registration. Clerks may request additional documentation (e.g., family registers, genetic test results) to verify compliance, particularly in rural prefectures where consanguinity is more prevalent.