A. You must apply for a PERMISSION TO ACQUIRE STATUS OF RESIDENCE.

Birth babies or those who have withdrawn from Japanese citizenship and become foreigners having no status of residence.
If you wish to continue to stay in Japan, you must proceed.

At this time, over 60 days from the day of birth or withdrawal of nationality can stay in Japan, it will be illegal stay.

In order to obtain status of residence, you must apply for a PERMISSION TO ACQUIRE STATUS OF RESIDENCE within 30 days from the day of birth or withdrawal from your nationality.
Even with birth, there are various cases, such as cases of regular marriage, cases other than marriage, etc. Not only the immigration law but also the nationality law will be involved.

Anyway, since it is necessary to apply within 30 days, it is better to move early.

The Japanese nationality law does not take birthplace principles and even if born in Japan, foreign children are foreigners.