From Wikipedia; Pachinko is a Japanese gaming device. A pachinko machine resembles a vertical pinball machine, but has no flippers and uses a large number of small balls. The player fires balls into the machine, which then cascade down through a dense forest of pins. If the balls go into certain locations, sequences of events are triggered that result in more balls being released; these balls can then be exchanged for prizes. Pachinko machines were originally strictly mechanical, but modern ones have incorporated extensive electronics, becoming similar to video slot machines.
The machines are widespread in establishments called parlors, which feature a number of slot machines; hence, they operate and look similar to casinos. Modern pachinko machines are highly customizable, keeping enthusiasts continuously entertained. Because gambling for cash is illegal in Japan, balls won cannot be exchanged directly for cash in the parlor; instead the balls are exchanged for tokens, which are then taken outside and exchanged for cash at a place nominally separate from the parlor and possibly run by organized crime.