2025-03-24

In Japan, so-called “dual nationality” is not recognized, so if a Japanese citizen acquires a foreign nationality of his/her own volition, he/she is required to report to renounce his/her Japanese nationality. If this procedure is not completed within a certain period of time, the person will be left holding two nationalities.

What is nationality?

Nationality is a qualification for a person to be a “member” of a particular country. For a country to exist, territory and citizens are essential. Therefore, all countries have the concept of “nationality. However, the definition and determination of nationality differs depending on the history, culture, social conditions, etc. of each individual country.

In Japan, there are three ways to acquire nationality.

The first is birth. According to Japanese law, a child acquires Japanese nationality when either the father or mother is Japanese, or when the father is Japanese and dies before birth, or when both parents are unknown or the child is born in Japan with no nationality.

The second method is by notification. If certain requirements (such as recognition) are met, notification to the Minister of Justice will result in acquisition of Japanese nationality.

The third is naturalization. If a foreign national wishes to acquire Japanese nationality, he/she may apply for naturalization, and if the Minister of Justice grants permission, he/she may acquire Japanese nationality.

Prohibition of Dual Citizenship

Dual nationality is not allowed in Japan. For example, if a woman with Japanese nationality marries a foreign man in Japan, and the law of the man’s home country stipulates that “the one who becomes a wife shall acquire the nationality of the husband,” the woman will acquire the nationality of that country.

However, as explained earlier, dual nationality is not allowed in Japan. Therefore, the woman must choose which nationality she will become a citizen of by the time she turns 22 years old or by the time she has been a dual citizen for two years, whichever is later.

What is a case of renouncing Japanese nationality?

If a Japanese citizen voluntarily applies for and acquires foreign nationality, she automatically renounces her Japanese nationality. This is because the provisions of the Nationality Law, Article 11, Paragraph 1, “A Japanese citizen loses Japanese nationality if he/she acquires the nationality of a foreign country at his/her own volition.” This is because the provision “If a Japanese citizen acquires the nationality of a foreign country at his/her own will, he/she loses his/her Japanese nationality.

However, if the acquisition of a foreign nationality is not reported to the local municipal office, the person will always be a Japanese citizen in the family register, and thus will have dual nationality.

Article 103, paragraph 1 of the Family Registration Law states, “Notification of loss of nationality must be made by the applicant, spouse, or relative within the fourth degree of kinship of the applicant within one month of the date of knowledge of the loss of nationality (or within three months if the person to whom notification should be made is outside Japan on the date of knowledge of such fact). This means that the foreign nationality is not required to be reported within one month after the acquisition of foreign nationality.

In other words, the applicant, spouse, relative, etc. must notify the municipal office within one month of learning of the acquisition of foreign nationality. However, if the person who must notify is not in Japan, it must be done within three months.

Conclusion

Dual nationality is not allowed as long as one resides in Japan. In other words, there is a choice between Japanese nationality and foreign nationality. If you voluntarily acquire a foreign nationality, you will not automatically lose your Japanese nationality. It is necessary to report it at the municipal office of the city, ward, town or village.