ID number system kicked in 2016
A comprehensive ID number documentation system (My Number) put in practice in Japan in 2016. But the database of this system is used for official purposes only. Therefore, just for ID verification purpose s, complicated double documentation system is still in use:
- Residential registration system for municipal government or “Juminhhyo“
- Family registration system or “Koseki“
Residential registration is registered at a city hall where you reside. When you move from one place to another, you must register your new address to the city hall you move in within 2 weeks. Every time a resident moves moving record can be traced from previous city hall. But since the registration is only filed only in the database for each city hall based on the strict sectionalism, it’s not easy to locate an address without previous city they used to live.
Family registration or Koseki can be obtained from name and legal domicile or Honseki. As a resident registration keeps a record of legal domicile, theoretically, Koseki information can be obtained from name and resident address.
A legal domicile (permanent address) or Honseki used to be an ancestral address, but now it only plays a role of temporal ID number because you can single out any legal domicile in all over Japan.
Not publicly available
Resident registration and family registration is strictly confidential. They are supposed to be disclosed only to the person himself, authorized professionals such as lawyers and municipal governments.