Japan to Cut Off Japanese? Protecting the ties between Japan and the Japanese citizens who are successful overseas

Consulting Fellow, RIETI

1. Japan's Regulations Prohibiting Multiple Nationality

Did you know that Japanese nationals can lose their Japanese citizenship?

In September 2023, the Supreme Court rejected a lawsuit by a Japanese national living abroad who claimed that the provision on the loss of Japanese nationality upon acquiring foreign nationality violated the Constitution, ruling that this provision was constitutional (Note 1). In 2019, it will be remembered that Naomi Osaka, a tennis player with dual Japanese and U.S. citizenship, submitted notification of her choice of Japanese citizenship (Note 2).

These cases involving nationality (citizenship) highlight the risk of losing internationally successful Japanese nationals due to Japan’s lack of recognition of multiple nationality. Multiple nationality (Multiple citizenship) is the possession of more than one nationality, either by birth or through later acquisition of a foreign nationality. Multiple nationality by birth is obtained when a child is born and meets the requirements for being granted nationality by more than one country (broadly speaking, there are two types: jus sanguinis, which grants nationality to children of nationals, and jus soli, which grants nationality to children born within the country). For example, a Japanese child born in the U.S. can acquire both Japanese and U.S. citizenship. Alternatively, a person becomes a multiple national if he or she fulfills the requirements for acquiring foreign nationality by living in a foreign country for an extended period of time or through an international marriage. Most multiple nationality cases are in fact dual nationality, but in this column, "multiple nationality" is used, as an individual may have three or more nationalities if his or her parents have different nationalities or he or she was born in a country that is different from that of his or her parents, or if a person with dual nationality later acquires the nationality of another country.

The ruling of the Tokyo District Court in the first instance (January 21, 2021), which was upheld by the Supreme Court at the beginning of the article, stated that the reason for not allowing multiple nationalities is that the concept of one nationality per individual is derived from the essence of nationality. It also pointed out that the problems with multiple nationality include the conflict of diplomatic protection rights from multiple countries for one individual, obligations such as military service and tax payment in multiple countries, and the possibility that having multiple passports may not allow for appropriate control of cross-border movement. It further held that enjoying rights as a citizen in more than one country is not something that needs to be protected as it is not held by a person with a single nationality.

However, the plaintiffs' complaint in this case highlights desperate situations in which Japanese nationals must acquire foreign nationality for professional or family reasons. Depriving Japanese nationals who are successful overseas of their Japanese citizenship because they have acquired foreign citizenship under such circumstances not only causes suffering and disadvantages them: it also represents a serious loss to Japan (Note 3).

2. Prohibition of multiple nationality in exceptional cases

According to the Ministry of Justice, more than 20,000 people have renounced or lost their nationality in the 10 years from 2013 to 2022. This includes many citizens who have lost their nationality against their will (Note 4). In addition, many overseas residents are hesitant to acquire nationality in their country of residence for fear of losing their Japanese citizenship.

The actual number of Japanese nationals with multiple nationalities is not clear. It is estimated that approximately 890,000 Japanese citizens have become multiple nationals by birth, and several hundred thousand have become multiple nationals by acquiring foreign citizenship. The number of Japanese citizens living overseas has increased significantly in recent years. In 2019, the number of Japanese citizens who reported living overseas alone totaled approximately 1.41 million (including 520,000 permanent residents with foreign residency rights). In 1990, there were 620,000 citizens living overseas (including about 240,000 permanent residents), so the number has more than doubled in 30 years (Note 5). Approximately 520,000 foreign permanent residents potentially have a need for multiple citizenship.

The number of countries that recognize dual nationality is increasing, reaching about 70% of the world's population. These countries include those that recognize multiple nationality only with certain countries, and countries that do not recognize it in principle but do so under certain conditions. However, Japan uniformly prohibits multiple nationality, so when a Japanese person voluntarily acquires a foreign nationality, he or she loses Japanese nationality. In addition, persons with multiple nationalities by birth must choose their nationality by the age of 20 (Note 6). Furthermore, under the current system, if a Japanese national acquires a foreign nationality, his/her Japanese nationality is automatically retroactively revoked if the authorities become aware of the acquisition, even if the individual does not report it, without any opportunity to explain or change his/her nationality. Fearing that losing their nationality would result in a lack of protection from the state and restrictions on entry and residence, Japanese nationals with multiple nationality often do not declare their status, so the government is unable to ascertain their actual status. In addition, multiple nationals live with the risk of being discovered and suddenly losing their nationality.

However, the current situation in which Japanese nationals can acquire foreign nationality but cannot declare it, increases the risk of diplomatic problems and unclear immigration controls resulting from the "conflict of protection rights of various countries," which is one reason the government decided not to allow multiple nationality. As in the case of the 2023 Hamas attack on Israel, in which the victims included multiple nationals from Israel and a third country, there may well be situations in which both nationalities are more concerned about the victims' safety than the "diplomatic friction caused by clashes of protection rights" that the Japanese government fears. In fact, if a Japanese national is found to have another country's nationality for the first time when he or she is taken hostage overseas, it may hinder the government's initial response and lead to a diplomatic problem. Japan can legally resolve the issue by saying that they are no longer protected because they ceased to be Japanese citizens when they acquired foreign nationality, but how would that be viewed by the international community? It would be more realistic to allow multiple nationality and keep track of nationality and immigration information to resolve the government's concerns.

Nationality can be extremely important in establishing a basis for living abroad, including issues related to employment or marriage. Applicants may not be eligible to apply for a post if there are nationality requirements for employment or academic research. In addition, just as the COVID-19 pandemic restricted the entry of foreigners, they may not be able to enter the country where their family members are located without such nationality in the future. A foreigner's permanent residence or residence permit may be revoked by a decision of the government. Some countries automatically grant nationality to the spouses of internationally married citizens, which may still result in multiple nationality and loss of Japanese citizenship.

The current policy of Japan is to confront these individuals with the difficult choice of whether to choose foreign citizenship to live overseas with their spouses and children, or to choose Japanese citizenship for the long-term care of their old parents in Japan. In addition, although people with multiple nationalities by birth are obliged to choose their nationality by the age of 20, most of them are not even employed yet, and it is too early for them to decide which nationality they will need in the future, although they are otherwise capable of making such a decision at the age of 20.

3. Toward a future in which we do not lose Japanese people

In order to change this situation, I believe it is necessary to allow multiple citizenship. Instead of uniform recognition as in the U.S., a policy could be adopted, as in Germany, which does not recognize multiple nationalities in principle, but allows it on an exceptional basis in cases of dual nationality with a neighboring country or the U.S., or in circumstances where serious economic loss would occur (Note 7). The Japanese government states that, in principle, when a foreign national naturalizes, they lose their original nationality; however, if the law of the country does not allow them to renounce their nationality, naturalization is permitted under special circumstances, while retaining multiple nationalities. As for persons with multiple nationalities by birth, renunciation of foreign nationality after choosing Japanese nationality is considered an "effort obligation," and many people do not actually do so. In comparison, the treatment of Japanese nationals who have been granted multiple nationality not through birth is extremely uniform and rigid.

Is it a "privilege" unworthy of protection for a person with multiple citizenship to have rights as a citizen, such as entry, residence, and welfare, in more than one country, as was determined in court? It is no longer unusual for an individual to have an identity or basis of livelihood in more than one country, and such people are merely seeking basic rights as citizens of both countries. Another problem is that multiple nationality makes one subject to obligations as a citizen of each country, such as military service and tax payment, which is still occurring even in the current situation. Military service is imposed from the age of 18 in most countries (which is below the mandatory age for choosing Japanese nationality), so some Japanese nationals with multiple nationalities by birth already have military service obligations in other countries as well. It would also be possible to enter into bilateral agreements between states, as is already done for tax payments and pensions.

In an increasingly globalized world, any Japanese person can be affected by issues related to having multiple nationalities. A Japanese person who never expected to leave Japan could still marry a foreigner in Japan. Children of a Japanese family may not be able to return to Japan permanently because he or she has acquired foreign nationality. About 30 years from now, in 2056, the total population of Japan will fall below 100 million(Note 8). On the other hand, the number of Japanese citizens who are successful around the world is increasing. Creating a system that allows Japanese nationals to work both in Japan and overseas is necessary for Japan's growth, and allowing multiple citizenships is an important step in this direction.

December 22, 2023
>> Original text in Japanese

  1. ^ As of December 2023, the plaintiffs have filed a motion for another trial (request for retrial) in this case.
  2. ^ It is not clear whether he has taken steps to renounce his U.S. citizenship to the United States. Strict procedures and examinations are required by U.S. law for renunciation of U.S. citizenship.
  3. ^ For example, as an opinion of the parties involved, "Japan not recognizing dual nationality, over 70% of the world's 150 countries accept it, 'loss' against one's will, unconstitutional lawsuits," Mainichi Shimbun online edition, March 5, 2020, https://mainichi.jp/articles/20200305/k00/00m/010/062000c (in Japanese).
  4. ^ Ministry of Justice website, "Number of Applicants for Naturalization Permits," April 27, 2023,
    https://www.moj.go.jp/MINJI/toukei_t_minj03.html (in Japanese).
  5. ^ "Dual Citizenship, '890,000' in Japan, World Accepts, Benefits Businesses," NIKKEI STYLE, October 23, 2018, https://www.nikkei.com/article/DGXMZO36579310X11C18A0EAC000 (in Japanese).
  6. ^ Articles 11 and 14 of the Nationality Law.
  7. ^ "Dual citizenship - multiple nationalities," Federal Ministry of the Interior and Community,
    "Retention Permit to keep German citizenship when naturalizing in the US / 'Dual citizenship,'" German Missions in the United States website,
  8. ^ National Institute of Population and Social Security Research, "Population Projections for Japan: 2021 to 2040," 2023.

January 12, 2024