Japan's official record of every Japanese national's family history — births, marriages, divorces, deaths, and more. A complete guide to understanding the koseki system and obtaining records from outside Japan.
The koseki (戸籍, literally "household register") is Japan's system for recording vital events in the lives of Japanese nationals. Maintained by municipal offices (shi, ku, machi, and mura) across Japan, the koseki has been the official record of births, deaths, marriages, divorces, and family relationships since its modern form was established in 1872.
Every Japanese national is registered in a koseki page at the municipal office of their honseki (本籍) — their registered place of family origin. The honseki is not necessarily where a person lives or was born; it is an administrative designation inherited from parents at birth. A person living in Tokyo may have a honseki in Osaka; a Japanese national living overseas still has a honseki at some municipality in Japan.
Because the honseki is fixed to a specific municipality, requesting a koseki always means contacting that specific office — you cannot request it from any municipal office, only the one that holds your register.
There are three main categories of koseki record, determined by whether the register page is currently active and when it was created.
The current, active family register. A tohon (謄本) is a full certified copy of the entire page; a shohon (抄本) is a partial extract listing only specified individuals. The tohon is most commonly required for overseas purposes. Full guide to koseki-tohon →
A removed or closed register page — one where all members have transferred out, or which was closed when Japan reformed its registration system. Because Japan periodically restructures the koseki, records from older generations are almost always held as joseki. Essential for tracing ancestry beyond the current generation.
The original register as it existed before a major national koseki reform — most commonly the 1947 Civil Code reform or the 1994 computerization reform. Pre-reform registers often contain richer family data spanning more generations on a single page. Required when the information needed predates the current register format.
A koseki page records all registered members of a household and the vital events that affect them. The specific fields have changed across reforms, but a modern koseki-tohon typically includes:
These two documents are often confused but serve different purposes.
Core questions about the Japanese family register system.
Most clients come to us knowing their goal, not the exact document name. That's fine — describe what you're trying to accomplish and we'll identify which koseki records are required.
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