2025-07-16

Nationality refers to “the qualification for a person to be a member of a particular country. However, the rules concerning nationality vary from country to country. In Japan, having multiple nationalities is prohibited in principle. The following is an explanation of the exception to the rule, “reservation of nationality.

Rules for Japanese Nationality

In Japan, a child born in Japan can acquire Japanese nationality if one of the parents has Japanese nationality. Even if the child is born abroad, if one of the parents has Japanese nationality, the child can acquire Japanese nationality.

In other words, the rule in Japan is that a child can acquire Japanese nationality as long as one of the parents is Japanese, regardless of which country the child was born in. This is called the “bloodline principle.

What is the reservation of nationality?

I explained earlier that in Japan, if one of the parents has Japanese nationality, the child will have Japanese nationality. In the U.S., however, a child born in the U.S. can acquire U.S. citizenship regardless of the nationality of the parents. This is called the “fabric principle.

According to both Japanese and U.S. rules, a child born to Japanese parents residing in the U.S. would acquire two nationalities, American and Japanese.

In Japan, dual citizenship is not allowed, but a child can have both Japanese and U.S. citizenship by submitting a “notification of reservation of nationality” to the Japanese embassy or other authorities in the U.S. within three months of birth. If the notification is not filed, the applicant will not be able to acquire Japanese citizenship, but only U.S. citizenship.

This system of “reservation of nationality” is literally a “reservation of Japanese nationality” so that the child can live as a Japanese citizen after returning to Japan in the future. However, if the child lives in Japan, the child must choose one of the two nationalities, as Japan does not recognize dual nationality.

Notes on the Reservation Period

If a child is born with dual nationality and has not yet chosen either nationality, “Reservation of nationality” will be noted in the family register. Specifically, the following information will be entered in the “Birth” column of the family register under “Status”.

　Date of notification of reservation of nationality: 2021 XX year XX day

　Date of receipt: XXXX, 20XX

　Ambassador of the country of residence

During the period of reservation of nationality, the applicant has dual nationality and can hold passports of two countries.

In principle, under Japanese domestic law, a person must choose one of the two nationalities by the time he/she reaches the age of majority. Article 14 of the Nationality Law stipulates the following

　・If a person becomes a dual national before reaching 18 years of age, he or she has until the age of 20.

　・If the dual nationality occurred before the age of 18, it must be done within 2 years from the time of dual nationality.

Summary

Japan does not recognize “dual nationality,” but if you were born in the U.S., for example, you can have both Japanese and U.S. citizenship. In this case, a “notification of reservation of nationality” must be submitted to the Japanese embassy. However, since this is only a “reservation of nationality,” the applicant must choose which nationality to become by a certain age.