We had signed up for acquirement of nationality of children who was recognized as Japanese's child today.
The general naturalization takes about 1 year for procedure but only 2 months needed in case of acquirement of nationality.
There are 3 ways to get Japanese nationality: "At the time of birth",”Acquirement of nationality” and "Naturalization"
Get Japanese nationality "At the time of birth"
Children's father or mother is Japanese at the time of his/her birth
※With children born outside Japan, "reservation of Japanese nationality" must be submitted within 3 months since the birth
Get Japanese nationality by "Acquirement of nationality"
Under 20 years old and satisfy the following conditions
Recognized as Japanese's children by his/her own Japanese father
Children born outside Japan who didn't submit "reservation of Japanese nationality"
Get Japanese nationality by "Naturalization"
Foreigner who not have Japanese nationality, after satisfy all fixed conditions may get Japanese nationality by "naturalization" formalities
For more details about "naturalization"
There are many methods to get Japanese nationality. Especially, children who was born between no marital status of foreigner mother and Japanese father mostly get Japanese nationality by "Notification"
For more, a foreigner mother has higher possibility to change her status of residence (visa) to long-term visa and live in Japan with children as "bring up person of Japanese"
For more details about "Acquirement of nationality"