2025-07-01

We use the terms “nationality” and “Japanese nationality” in our daily lives. I am sure that there are quite a few people who can answer immediately when asked, “What is (Japanese) nationality? Here, we will explain “What is nationality? and “What is the definition of Japanese nationality? in detail.

What is nationality?

Nationality is a qualification for a person to be a “member” of a particular country. A “member” is a person who makes up an organization, group, etc.
In order for a country to be established, territory and citizens are essential. In other words, a nation cannot be established without its citizens. Therefore, every nation has its own concept of nationality, and every nation defines nationality according to its own standards.
However, since each country has its own history, traditions, politics, economy, etc., nationality is determined differently, and each country determines its own nationality according to its own judgment and standards.

What is the definition of Japanese nationality?

In the case of Japan, the criteria for “Japanese nationality” are defined by a law called the “Nationality Law. This law stipulates that there are three causes for a person to have Japanese nationality: birth, notification, and naturalization.
First is birth. A person may have Japanese nationality if one of the parents has Japanese nationality at the time of birth, or if the father who died before the birth had Japanese nationality at the time of death, or if both parents are unknown or stateless and the person was born in Japan.
Next is notification, which allows a person who meets certain requirements to become a Japanese citizen by submitting a notification to the Minister of Justice. This includes the re-acquisition of Japanese nationality by a recognized child or a person who did not reserve his/her nationality.
Finally, there is naturalization, which allows a foreign national who wishes to acquire Japanese nationality to apply to the Minister of Justice and, if approved, acquire Japanese nationality.

Loss of Japanese nationality

What are the cases in which a person who currently has Japanese nationality loses Japanese nationality? The Nationality Law provides for the following four main cases.
The first is the loss of Japanese nationality of one’s own volition. For example, if a person acquires foreign nationality of his/her own volition or becomes a naturalized citizen of a foreign country, he/she automatically loses Japanese nationality.
The second is the automatic loss of Japanese nationality when a person who has both Japanese and foreign nationality chooses foreign nationality in accordance with the laws of that foreign country.
Third, a person who has both Japanese and foreign nationality loses Japanese nationality when he/she notifies the Minister of Justice of Japan of his/her renunciation of Japanese nationality.
Finally, a child born abroad and having Japanese and foreign nationality by birth will lose Japanese nationality retroactive to the time of birth if he or she does not notify that he or she reserves Japanese nationality at the same time as submitting the birth notification.

Summary

Japanese nationality is nationality obtained according to the criteria established by Japan’s “Nationality Law. There are three causes for acquiring Japanese nationality: birth, notification, and naturalization. In addition, Japan does not recognize dual nationality, so a person who has both Japanese and foreign nationality will lose Japanese nationality if he/she chooses to become a foreign national.