Japanese Citizenship and the Nationality Law

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Up until 1984 Japan was a patriarchal society meaning that nationality could only be conferred through a Japanese father, not a Japanese mother. Per amendments made to the Nationality Law in 1984, nationality is now based on the child's parents' citizenship; therefore if one parent (male or female) or both of the child's parents are Japanese then the child automatically has Japanese nationality at the time of birth.  But the details of recognizing a parent differ depending on whether the Japanese parent is a man or a woman, whether the child is born in or out of wedlock, and if born out of wedlock to a Japanese father whether the father acknowledged paternity before birth or after birth.  So read this page carefully.

Birth to Japanese father

Japanese law legally recognizes a bona fide father-child relationship when a child is born to a man who has Japanese citizenship, only when one of the following conditions are met:

1. The child is the legitimate child of a Japanese man and his non-Japanese wife. I.e. the child was born in wedlock.  The child may be born inside Japan or born  outside Japan, it must be registered properly on the father's koseki by submitting the appropriate forms.
2. The father acknowledged paternity before birth, i.e. while the mother was pregnant by submitting the appropriate forms for taiji ninchi to a local government office (the one who holds his koseki.)  For more information on this please see the section Child Born Out of Wedlock in Japan or Child Born Out of Wedlock Outside Japan
3. If the father submits an after-birth ninchi application and then marries the father at any time before the child's 20th birthday, the child will get Japanese citizenship.  This Civil Law process is called the junsei (準星) process. There are two patterns in which the "junsei" process may take place; 1) The biological Japanese father legitimizes the child and the biological parents later marry; or 2) After the biological parents get married, the father legitimize the child by an after-birth ninchi application. In either case, the child's status becomes recognized as a legitimate child of the father. The important factor to keep in mind is that Japanese citizenship can only be conferred when the biological parents become legally married. In other words, a child cannot acquire citizenship only by the father filing papers to legitimize the child after birth. The "junsei" process papers may be filed at the nearest Legal Affairs Bureau (part of the Ministry of Justice) in their region. While the child is under the age of 15 this may be undertaken by a legal proxy.

Note that a Supreme Court case said this it is not legal to refuse citizenship to a child recognized by its parent AFTER birth.   This is a recent event and historically, citizenship was not granted to children recognized after birth.  There have been other reports that this was over-rules.  See our  page on Notable Japanese Court Cases page for more information.

Birth to Japanese mother

A mother-child relationship is recognized when a woman gives birth to a child. Law in Japan automatically recognizes a child is Japanese when a Japanese woman gives birth to a child. But note that if the parents are unmarried, the mother automatically gets full custody. The father has no rights by default and can be ordered to pay child support.

Naturalization

Naturalization (kika 帰化) may be possible, but with out being able to prove Japanese ancestry, i.e. it is likely to be just like any other foreigner.  On the other hand, if the biological Japanese father recognizes the child after birth, the regulations are eased to allow the child of a Japanese citizen to be naturalized. As such a child can apply for nationalization "as a child of a Japanese".  If father refuses to legitimize a child, the case can be taken to court and the biological father can be forced to legitimize the child.

Adoption

<TBD> It is unknown whether adoption allows a child to acquire Japanese citizenship.

Laws

Acquisition

Here is a "change log" of the nationality law, written by Supreme Court justices in a case on " Judgment concerning whether a child who was born, out of wedlock, to a native Japanese mother and a Korean father and was acknowledged by the father after the enforcement of the Nationality Law loses Japanese nationality after the effectuation of the Peace Treaty" Note that this only covers law concerning acquisition of citizenship, not, for example, the prohibition against dual nationality.

References: Article 10 of the Constitution, Article 3 of the Common Law (Law No. 39 of 1918), Article 23 of the Old Nationality Law (before abolishment by Law No. 147 of 1950), Articles 8 and 9 of the Nationality Law (before amendment by Law No. 45 of 1984), Article 10 of the Nationality Law (before amendment by Law No. 268 of 1952), and Article 2(a) of the Treaty of Peace with Japan

Article 10 of the Constitution

The conditions necessary for being a Japanese national shall be determined by law.

Article 3 of the Common Law (Law No. 39 of 1918)

A person who enters a family in a region under the law of the region shall withdraw from a family in another region.

2. A person who may not withdraw from a family in a region under the law of the region may not enter a family in another region.

Article 23 of the Old Nationality Law (before abolishment by Law No. 147 of 1950)

A Japanese child shall lose Japanese nationality when he has acquired foreign nationality due to acknowledgement; provided that, however, this shall not apply if the child becomes a wife, husband, or adopted child of a Japanese national.

Article 8 of the Nationality Law (before amendment by Law No. 45 of 1984)

A Japanese national shall lose Japanese nationality when he has acquired foreign nationality of his own free will.

Article 9 of the Nationality Law (before amendment by Law No. 45 of 1984)

A Japanese national who was born in a foreign country and acquired nationality of the country by birth shall lose Japanese nationality retrospectively from the time of the birth, unless he declares his intention to retain his Japanese nationality in accordance with the provisions of the Family Registration Law (Law No. 224 of 1947).

Article 10 of the Nationality Law (before amendment by Law No. 268 of 1952)

1. A Japanese national who has foreign nationality may renounce his Japanese nationality.

2. Such person who intends to renounce his Japanese nationality shall make notification to the Director-General of Justice.

3. Such person who has renounced his Japanese nationality shall lose Japanese nationality.

Dual Nationality

These are being summarized by Japan CRN

Article 14 of the Nationality Law (as of sometime in the 2000's)

1. A Japanese national having a foreign nationality shall choose either of the nationalities before he or she reaches twenty two years of age if he or she has acquired both nationalities on and before the day when he or she reaches twenty years of age or, within two years after the day when he or she acquired the second nationality if he or she acquired such nationality after the day when he or she reached twenty years of age.
2. Choice of Japanese nationality shall be made either by depriving himself or herself of the foreign nationality or by the declaration provided for in the Family Registration Law in which he or she swears that he or she chooses to be a Japanese national and that he or she renounces the foreign nationality (hereinafter referred to as “declaration of choice ”).