Category
Koseki
2025/06/06 BLOGAttorney Tawara Kojiro
Hello, This is Attorney TAWARA.
As a lawyer, I also often receive inquiries from foreign nationals regarding the family register (koseki).
Therefore, today I would like to talk about the family register.
As a lawyer, I also often receive inquiries from foreign nationals regarding the family register (koseki).
Therefore, today I would like to talk about the family register.
What is Koseki?
This may sound complicated at first, but let me explain:
The elements that identify a person (for example, name, sex, date of birth, parentage, marital status, etc.) constitute what is referred to as a person’s status (Mibun).
Koseki is the system in which information related to a person’s status—ranging from birth to death (such as a change of name, change of sex, or marriage)—is recorded.
The elements that identify a person (for example, name, sex, date of birth, parentage, marital status, etc.) constitute what is referred to as a person’s status (Mibun).
Koseki is the system in which information related to a person’s status—ranging from birth to death (such as a change of name, change of sex, or marriage)—is recorded.
What is written in Koseki?
In addition to the registered domicile (honseki), the family register records the following:
- Name
- Date of birth
- Cause for being entered into the register (such as birth or marriage)
- Names and relationship of the natural parents
- In the case of adoption, the names and relationship of the adoptive parents
- Spouse status (husband or wife)
- Indication of prior koseki in cases where a person moved from another koseki
What is the Registered Domicile (Honseki)?
An important concept is honseki (registered domicile).
The honseki refers to the location in Japan where a person’s koseki is maintained.
The municipality where the register is located is called the honseki-chi (registered domicile locality).
In contrast, address (jūsho) refers to one’s actual residence, and does not necessarily coincide with the honseki.
The address and honseki are distinct concepts.
When is Koseki Used?
Many Japanese are aware that a certified copy of the family register (koseki tohon) is required when applying for a passport.
Additionally, when a foreign national is naturalized in Japan, a family register is created.
I often review family registers in connection with inheritance inquiries.
Examples of such inquiries include:
Additionally, when a foreign national is naturalized in Japan, a family register is created.
I often review family registers in connection with inheritance inquiries.
Examples of such inquiries include:
- “A family member has passed away and I obtained koseki, but a relative resides overseas—how should the inheritance be handled in such a case?”
- “A family member has passed away and I obtained koseki, but the name of a person I don’t know from a foreign country is listed—how should I contact this person?”
If You Have Any Issues Regarding Koseki, Please Consult Our Office
The family register system can be difficult to understand, even for Japanese, and it may be even more so for foreigners.
If you have any concerns or issues regarding koseki, please feel free to contact our office
If you have any concerns or issues regarding koseki, please feel free to contact our office