[Question] My Japanese spouse and I had a baby in Japan. Which nationality does our newborn acquire? How and where should we report the birth? How is the baby’s family name determined?

Birthright citizenship is conferred either by jus sanguinis (citizenship attribution by parentage) whereby a child takes its citizenship from his parent, or by jus soli (citizenship determined by the place of birth) by which citizenship is extended to any individual born in the territory of the state. Japan adopts the dual system of jus sangiunis, whereby citizenship is transmitted to a child if either of its parent is a citizen of the state. Depending on the law of your country, your child acquires citizenship of your country and keeps dual nationality.

Registration of Birth with your city office should be completed within 14 days of the birth of your child. If your government extends nationality to your child, you also have to report its birth to your embassy or consulate general in Japan within a specified timeframe. A Japanese child with dual nationality is treated as Japanese under Japanese law and a resident certificate will be created upon registration of the child’s birth.

Your child takes your Japanese spouse’s surname because he will be entered in the family registry of the Japanese parent. If you want your child to have your foreign family name, there are ways to do so.