Gambling in Japan is a curious mix of strict laws and surprising exceptions....

https://yenkee-wiki.win/index.php/Where_Can_I_Check_Official_Info_on_Horse_Racing_in_Japan%3F

Gambling in Japan is a curious mix of strict laws and surprising exceptions. While most forms of betting are illegal, a few government-regulated games like pachinko, horse racing, and keirin cycling races offer legal ways to try your luck