In rummy, the joker is a flexible card which can replace a missing card in a sequence or set. There are two types of jokers in rummy. The first is the card which has a physical image and wording showing it’s a joker. This is also known as a printed joker. The second is a randomly selected card – say, the jack of hearts – which can then act as any card in the deck. The card which will represent the joker is decided before play begins.