Japanese Naturalization

Japanese nationality is a legal designation and set of rights granted to those people who have met the criteria for citizenship by parentage or by naturalization. Nationality is in the jurisdiction of the Minister of Justice and is generally governed by the Nationality Law of 1950.

Japan is a strictjus sanguinis state as opposed to jus soli state, meaning that it attributes citizenship by blood and not by location of birth. In practice, it can be by parentage and not by descent. Article 2 of the Nationality Act provides three situations in which a person can become a Japanese national at birth:

A system for acquiring nationality by birth after birth is also available. If an unmarried Japanese father and non-Japanese mother have a child, the parents later marry, and the Japanese father acknowledges paternity, the child can acquire Japanese nationality, so long as the child has not reached the age of 20. Japanese nationality law effective from 1985 has been that if the parents are not married at the time of birth and the father has not acknowledged paternity while the child was still in the womb, the child will not acquire Japanese nationality. However, Japan's Supreme Court ruled in 2008 that denying nationality to children born out of wedlock to foreign mothers is unconstitutional.

Naturalization in Japan requires the applicant to give up their current citizenship(s) either before or after, depending on the nationality, the naturalization takes place if the loss of nationality does not occur automatically. The Japanese government does not have strict rules for the naturalization process, even though the documents that need to be collected for application from the applicant's home country might take quite some time. Basic naturalization requirements differ from person to person regardless of what country the applicant is from and depending on the applicant's current status in Japan. Unlike most other countries, the applicant does not have to be a permanent resident to be eligible to apply for Japanese naturalization.

The criteria for naturalization are provided in Article 5 of the Nationality Act:

...
Wikipedia