it is a pachinko game token...pachinko gambling in Japan is very odd by our standards and it is all over the place...personally when i go i find it to be pretty tame boring stuff but a lot of folk spend serious bucks on it. and you can't actually "win" money...here this is from Wikipedia...
In pachinko, when a player's ball makes it into a special hole to activate the slot machine and a jackpot is made, they are rewarded with more balls. Players can then exchange the balls for prizes of different value at a booth in the parlour. Money cannot be awarded at pachinko parlors as this would be in violation of the criminal code. However, players almost always exchange pachinko balls for special tokens, usually slits of gold encased in plastic, and then "sell" them at a neighboring shop for cash. Usually such shops are also owned by the parlor operators, but as long as the winners do not receive cash in the parlour, the law is not broken.