How To Find Family In Japan

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Old Koseki

Koseki records are the perfect family tree generators

Koseki records are the perfect family tree generators
To trace a relative in Japan or create a complete family tree of a Japanese family, you need to obtain the Koseki family registry records, which comprise the fundamental citizen documentation system in Japan.

However, these records are strictly confidential, and you can’t get access to them without knowing the Honseki, the legal domicile of the Koseki records.

It is often the biggest obstacle to locating relatives in Japan, especially in the case of overseas customers on assignments or non-Japanese customers living in Japan.

Problems of Koseki Records

There are two citizen documentation systems in Japan: Koseki family registry records and Juminhyo residential records. Both types of documents are strictly confidential. The only people who can get access to those records are the person himself or herself, the direct lineal descendants/ascendants, attorneys, accountants, and other professional license holders.

To obtain Koseki family registry records, you need to provide Honseki (permanent domicile) information to the city hall of your jurisdiction. If you don’t know the Honseki, you can verify it via the Juminhyo records.

But the problem is that Juminhyo records get obsolete five years after the transfer at the local city hall. Therefore, if a subject moves out from an old address, there is no way we can obtain his/her Juminhyo residential records, which means it is the end of the game.

And if the client doesn’t even know a previous address or Honseki, the game’s over. There is no way to find Honseki, and there is no database you can search for Honseki in Japan.

Koseki and Juminhyo


Koseki Sample EN JP

A Koseki (戸籍) is a Japanese family registry.
It records the births, acknowledgments of paternity, adoptions, disruptions of adoptions, deaths, marriages, and divorces of all Japanese citizens. All Japanese citizens are required to set their Honseki (本籍 permanent domicile) in Japan and report all family events to the local city halls where they have set their Honseki.

Koseki (Wikipedia)


A Juminhyo (住民票) is a registry of current residential addresses. All citizens are required to report their current addresses to the local city hall. A Juminhyo records Honseki information for Japanese nationals.

Juminhyo (Wikipedia)

How To Obtain Koseki Records

Here is the quick guide for how you obtain Koseki records of your target.

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