Or if you're "Japanese" but with Korean heritage... I've heard stories of people who had Korean ancestry and they had a deep terror of anyone ever finding out.
After WW2, there was over 1 million Koreans living in Japan. Some went back, some decided to wait due to the war starting.
Then the country they were going back to no longer existed, so they stayed. Many don't even have citizenship.
https://www.nytimes.com/2005/04/02/news/japanborn-koreans-li...
I also remember hearing about how Pachinko parlours are usually owned by Yakuza/Zainichi and they funnel profits into North Korea.