Mario can get hints on how to find the casino from a sleeping Toad in Nimbus Land's inn. In one of the pipes in the center of the valley, Mario has to defeat a Chomp Chomp and jump three times to make an invisible platform appear, which opens the way to the casino.
The casino can be entered through a secret passage in Bean Valley.
The casino is run by the jester Grate Guy, and can only be accessed with a Bright Card acquired from his partner Knife Guy. Grate Guy's Casino is a secret area in Super Mario RPG: Legend of the Seven Stars.
