JapanDoes common-law marriage have legal protection?
Japan does not recognize common-law marriage; only registered marriages under the Civil Code have legal effect. Unregistered cohabitation confers no spousal rights or protections.
What the Law Says
Japanese family law mandates marriage registration (Civil Code Article 739) to establish legal marital status. Cohabitation alone, regardless of duration or intent, creates no legal relationship.
Courts consistently reject claims for spousal support, inheritance, or property division based solely on cohabitation. The Supreme Court has affirmed that marriage requires registration—not shared life or public acknowledgment.
Without registration, partners are treated as unrelated individuals for tax, immigration, health insurance, and inheritance purposes.
What to Do
Register your marriage at a municipal office (city hall) to obtain full legal protection.
Consider a written cohabitation agreement for limited practical arrangements—though unenforceable as marriage, it may guide property or support disputes.
Sources
Not legal advice. This article is general information based on publicly available sources, written for educational purposes. Laws change and individual situations vary. Consult a licensed attorney in your jurisdiction before acting on anything you read here. Last reviewed: 2026-06-09.