There are 2 Jokers in each game of Rummikub. Each Joker can represent any color and any number. Jokers can be used in groups and runs, and both jokers can be used in a single group or run. Once a Joker is on the mat, players can replace it with a suitable tile from the mat or from their rack.

In simple terms, 52 playing cards plus a joker are shuffled and pinned face down on a board, like a cork board.