"Waves of sound rolled from the arcades and pachinko parlors."

Pachinko
Creative Commons AttributionPachinko - Credit: Paul Downey
A Pachinko machine is similar to pinball or slots.

Small steel balls are loaded into the machine. Pull the flipper and most of the balls disappear, but a few find their way into special holes that activate the slots. Shoot and aim for the main pockets. If you match three images you win a jackpot.