 dies before the birth and is a Japanese national at the time of death (limited to fathers until 1985)

A system for acquiring nationality by birth after birth is also available.If an unmarried Japanese father and non-Japanese mother have a child, the parents later marry, and the Japanese father acknowledges paternity, the child can acquire Japanese nationality, so long as the child has not reached the age of 20.Japanese nationality law effective from 2020 has been that if the parents are not married at the time of birth and the father has not acknowledged paternity while the child was still in the womb, the child will not acquire Japanese nationality.