In the wake of opposition Democratic Party leader Renho's July 18 disclosure of her family register to prove that she has given up her Taiwanese citizenship and is now solely a Japanese national, The Mainichi answers some questions readers may have about dual nationality rules in Japan.
Question: How is it decided whether someone is a Japanese citizen?
Answer: Aside from immigrants who become naturalized Japanese citizens, Japanese nationality is based on the principle of "jus sanguinis," Latin for the "right of blood." That is, a person automatically becomes Japanese at birth if at least one of their parents is a Japanese national.
Q: What if one of the child's parents is not Japanese, or if they're born outside Japan?
A: The baby is still Japanese. If one of the parents is from another country that follows the "right of blood" citizenship principle such as Germany or France, then the baby automatically becomes a dual national. The child may also become a dual citizen if they are born in countries that base nationality not just on parentage but also on the principle of "jus soli," or "right of the soil," meaning citizenship is conferred on anyone born within the country's borders. Nations with jus soli-based citizenship include Canada and the United States.
Q: Does Japan recognize dual citizenship?
A: The Nationality Act does not recognize dual citizenship. A person with two or more nationalities must in principle choose to retain their Japanese nationality and give up any others, or give up their Japanese citizenship, by age 22. If the person chooses to be Japanese, they must either renounce their foreign nationality or abandon it through a formal declaration.
If someone does not declare their intentions before turning 22, and if they receive a notification from the minister of justice asking them to choose, they automatically lose their Japanese nationality unless they respond to the notice within a month of receipt. However, the Justice Ministry says that choosing a citizenship is essentially a voluntary act, and the minister has never actually sent a notice.
Q: So is it possible that a Japanese adult could actually keep a second nationality?
A: Even if the person makes a formal declaration giving up their other citizenship, the law only requires them to "endeavor to renounce his/her foreign nationality." Furthermore, there are no legal penalties for having dual citizenship.