Japan has a complex relationship with gambling that often puzzles visitors....
https://charlottessuperjournals.tearosediner.net/how-to-bet-on-horse-racing-in-japan-as-a-foreigner
Japan has a complex relationship with gambling that often puzzles visitors. While most forms are illegal, a few exceptions like pachinko parlours, horse racing, keirin cycling, and kyoutei boat racing are fully legal and popular