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What is a Koseki?

Koseki (戸籍) is an official Japanese family register, kept by the local city office.  It records many of the family events, such as births, deaths, marriages, divorces, and so on, that take place in a given family.  

In Japan, unlike the US and some other countries, there are NO official birth certificates, marriage certificates, or death certificates.  All Japanese citizens are required to keep their Honseki (本籍 permanent domicile) updated and report all family events to the local city hall of the Honseki.

In order to get a copy of a Koseki, you must either be listed on the Koseki yourself, or you must be able to document that you are a direct descendent of someone who is listed on the Koseki.

The first step in obtaining a copy of a Koseki is to determine where your ancestor lived.  This is often the most difficult step. was created to help with the problem of identifying the permanent domicile (the “honseki”) of your ancestor.

Unfortunately, the Koseki record will only be available at the local city office or townhall where your ancestor lived.  (Frustratingly, some people used the town where they were born, while other people used the town where they were living at the time.  It is very complicated…).  There is no publicly accessible database that can be searched to locate the proper “honseki”.  If you cannot determine where your ancestor lived, you cannot move forward.

One important thing to understand about doing family history research in Japan is that until after 1868 (the beginning of the Meiji era), only the elite nobility had family names.  The common person only had a first name.  

For the roughly 250 years prior to the Meiji era, Japan had been totally cut off from the rest of the world.  No one was allowed to leave and no one was allowed to enter the country.

When Japan re-opened its doors to the rest of the world, the Japanese government passed a law requiring ALL Japanese citizens to select a family surname.  So unless your family ancestor was a member of the nobility, tracing your family line back beyond 1868 can be very challenging.  

What is required to obtain our family Koseki?

Koseki records are strictly confidential as they contain personal information for all immediate family members. The only authorized people who have the ability to access Koseki records are immediate family members of direct lineal descendants, attorneys, accountants, and other professional license holders.

Requests for Koseki must be made to the City Hall where the family registry has registered itself. The Honseki can theoretically be anywhere yet, will commonly be the same “hometown” the Issei migrated from.

The challenge for most people is to research historic documents to generate sufficient “proof” of a direct lineage to your ancestors. This information must then be forwarded to the appropriate City Hall where records are warehoused.

This site was created to assist Japanese-American citizens the resources to effectively associate the old villages of the past to their modern day City Halls where records should be requested from.

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