Celery_boii Not true. Since 2011, Japan has the form where one has to state their citinzenship.
Goes like, (for my daughter, a Japanese citizen, passport) to state her citizenships.
1.
@Th**
2.
@Austr*****
3.
@Ja***
There, she has to say which citizenship takes precedence.
Japan and Australia were at war in the past. If there is a war again, if she is recruited in Japan, say as a nurse, she can decline to fight against her own country.
Before 2011, new Japanese citizens had to have their name (even changed) written in kanji. No more, can be written in katakana, a script for foreign names.
There are half million of Brazilians in Japan, mostly factory workers and their families. There is no way to rescind Brazilian citizenship, that is their Consttution.