The most popular variations of the game are Gin Rummy, Indian Rummy, and Kalooki, though it usually uses a standard 52-card deck. Regarding the number of players, the number of decks used, and particular new rummy listgameplay mechanics, each variation has its own set of regulations. In Indian Rummy, for example, players are frequently required to form at least two sequences, one of which must be a pure sequence devoid of jokers, whereas in Gin Rummy, players try to form melds and "knock" when their total number of unmatched cards is small. Anyone hoping to succeed in rummy must comprehend these fundamental concepts.
