Rummy is a group of matching card games notable for similar gameplay based on the matching cards of the same rank or sequence and same suit. The basic goal any form of rummy is to build melds which consists of sets, three or four of a kind of the same rank, or runs, three or more cards in sequence, of the same suit. The original form of rummy is called Sai rummy or Basic rummy. The Mexican game of Conquian is considered by David Parlett to be ancestral to all rummy games, which itself is derived from a Chinese game called Khanhoo and, going even further back, Mahjong. A book consists of at least three cards of the same rank or consecutive cards of the same suit. This is an almost universal pattern, although there exist minor variations, such as allowing only melds of the first type or requiring in melds of the second type that the cards are all of a different suit. In some games it is required that the melds of the second type contain at least four cards.
Contributions by 2005, Krenakarore, and Glenfarclas.