Can you become Japanese simply by marriage?

55% of weddings in Japan are "western" style (2014)

Often times, when people learn that I have Japanese nationality, they ask me, "are you married to a Japanese?" When I answer yes, they often say, "oh, that's why," perhaps concluding in their head that it was marriage that enabled me to obtain Japanese nationality.

However, many are then surprised to learn that marriage neither leads to automatic conferral of nationality nor is it necessary in order to get Japanese citizenship. Many unmarried people in Japan have an easier time naturalizing than they do acquiring their so-called "permanent" resident status (永住者資格 {eijūsha shikaku}) for their residency in Japan.

Historically†, there have been three ways to obtain nationality "automatically", or involuntarily, in the world:

• by where you were born (jus soli; 出生地主義 {shusshōchi shugi})
• by the nationality of your parents (jus sanguinis; 血統主義 {kettō shugi})
• by marriage (jus matrimonii; 婚姻主義 {kon'in shugi})

In some countries, religion, marriage, and nationality/citizenship (and sometimes even sex) are connected and sometimes inseparable (particularly in some Islamic states); marriage to a national of that country would confer, whether you desired it or not, the assumption of nationality and also religion on the person).

India abolished jus soli in 2004.

As a general rule of thumb, countries from the "Old World" of Europe and Asia tend to be jus sanguinis ("right of the blood"), whereas countries from the "New World", which were created by settlement from Europe, tend to be jus soli ("right of the soil"). Modern democracies tend to be a combination of the two with policies weighted towards one method, with the majority of the world favoring inheriting nationality from the parents, and if they do have jus soli, it is usually "restricted jus soli" (lex soli)‡.

Some countries restricted the inheritance of nationality to the father: paternal jus sanguinis (父系優先血統主義 {fukei yūsen kettō}). Japan, South Korea (ROK), and most other countries were like this. The United Nations however encouraged countries to have nationality laws which do not discriminate on the basis of sex, so many countries changed their nationality laws. Japan changed its nationality laws in 1985 so that it did not discriminate between boys and girls (父母両系血統主義 {fubo ryōkei kettō shugi}), which ended up retroactively giving nationality to many Japanese born in 1984 and before who had a father of foreign nationality.

男 {otoko}

There are still countries to this day, however, that only give or give preference to the nationality of the father. An incomplete list would include:

• Indonesia
• Sri Lanka
• Iraq
• Iran …

Japan's Nationality Law under the Meiji Constitution (1890~1947) had a concept of jus matrimonii (right by marriage) that was combined with its naturalization laws that were biased by sex:

If you were a foreign women that married a Japanese national, you could acquire Japanese nationality. However, if you were a Japanese woman that married a foreign national man, you lost your Japanese nationality — under the presumption that you would, in addition to the man's family name, be acquiring that foreign man's nationality as well!

However, this was not the only way for a foreign woman to acquire Japanese nationality: in addition to marrying a Japanese man, a foreign woman could naturalize and become a subject of the Japanese Empire. She did not have to marry to become Japanese. There are examples, such as ballerina 霧島エリ子 {KIRISHIMA Eriko} née Елена Павлова {Yelena PAVLOVA}, originally from the Russian Empire, who introduced Japan to the world of ballet and western social dance. She is enshrined in Yasukuni Shrine (靖国神社 {Yasukuni Jinja}) for her morale boosting service in Manchuria during wartime, although you do not have to be Japanese (or even human — animals are okay) to be enshrined there.

In the modern era, due to the separation of ethnicity, sex, and religion from civil marriage and civic nationality, there are not many countries left in the world that outright give nationality to somebody on the basis of marriage alone. Most countries consider marriage to be merely one variable in one's favor when considering granting either medium to long term (there's no such thing as permanent) residency status to a foreign resident or nationality to an assimilating immigrant. Other variables, such as one's finances, education, and behavior can disqualify you from becoming a citizen despite being married to a native.

Gérard Depardieu got Russian nationality over French tax use

In Japan's case, being legally married (civil unions and common law marriages do not count) in a marriage that is recognized by Japan, regardless of whether the marriage was done in Japan or overseas, providing the marriage is judged as stable and legitimate, can lead to either an easier path to permanent residency status (永住者資格 {eijūsha shikaku}) or to "simplified naturalization" (簡易帰化 {kan'i kika}), which simply means that the length of continuous time you need to be legally physically present in Japan is lowered from the minimum of five (5) years. Just because you are legally married on paper, however, does not mean your marriage will be judged as stable and legitimate: you will need to show that you have been living together for at least a few years, and both of you will be questioned during an interview process to see if you two have the type of familiarity with each other that spouses normally have.

Templo del Gran Jaguar

Still, there are still a few countries left that give considerable weight to marriage, above all the usual factors which determine naturalization eligibility, when it comes to nationality. Guatemala's nationality law, for example, gives extra special consideration to those who marry a Guatemalan national inside the country when it comes to naturalization:

Artículo 43. La extranjera que se case con guatemalteco podrá hacer la opción por la nacionalidad guatemalteca en las diligencias matrimoniales, cuando éstas tienen lugar en Guatemala, pero las demás formalidades deberán ser cumplidas en el Ministerio de Relaciones Exteriores, a efecto de que se reconozca la naturalización.

Translated:

Article 43. A foreign [female] national who marries a Guatemalan [male] may opt for Guatemalan citizenship when formalizing the marriage, if this is done in Guatemala; however, other formalities must be completed with the Ministry of Foreign Relations in order for the naturalization to be recognized.

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• † A rare exception: citizenship to the Vatican, technically a nation-state, is via jus officii — by appointment by an existing Holy See official only.
• ‡ Japan does not give automatic citizenship to Japanese diaspora such as Japanese-Brazilians, but per lex sanguinis, gives a foreign resident status of 定住者 {teijūsha} (long term resident), which is very similar to a permanent resident, to those of third generation or less that meet all the requirements.