If the other party goes to the hospital and gets a certificate of injury from a doctor, then you have to prepare a civil judgment, which means paying the other party's medical expenses and compensation. Therefore, if you want to get into a fight in Japan, make sure you provoke the other person enough to punch you and then fight back. Otherwise, you will definitely lose more than you gain. Never make the first move.
Why do I know this so well? Because the daughter of my mother’s friend’s relative (a high school girl) was bullied so pitifully by a Japanese boy in school that he couldn’t help stabbing her twice. As a result, the other party filed a complaint with the police station over this trivial matter. After that, the Chinese girl was called to the police station for questioning (for transferring to another school). Her mother panicked and found me through my mother’s friend. I went to the police station as a translator and helped them figure out the situation. The police My husband gave me a detailed explanation and I understood it so clearly.
Afterwards, her mother paid more than 700,000 yen in legal fees (they hired an ordinary Japanese lawyer) and compensated the other party for 50,000 yen in medical expenses. The incident happened in March this year and there is still no result.
If you encounter a criminal case, you will leave a "criminal record" and may affect your future life in Japan.
Please consider the consequences before fighting!