Gin rummy is a fast-paced variation on rummy, a card game which has a number of variations and permutations. Classically, gin rummy involves two players, although up to four people can potentially play, and the game is designed to go reasonably rapidly. It is also easy to pick up, making it a quick form of entertainment.
The rummy family of games all share the common trait of being draw and discard games, in which a player's turn starts by drawing a card, and ends with discarding a card. The goal of each player is to create “melds,” which can be matched sets of cards or runs of cards. As a general rule, a meld is three or more cards, while cards which cannot fit into a meld are known as deadwood. Scoring is performed by adding the values of cards which could not be worked into melds by the end of the hand.
In a classic hand of gin rummy, the dealer gives 10 cards to each player, and turns one card face up to start the discard pile, while leaving the rest of the deck face down to start the draw or stock pile. The opponent has the option of picking up the discard, or taking a card from the stock. He or she arranges the cards in the hand, selecting one to discard, and passing play to the next player.
The hand ends when a player goes out or “knocks,” knocking the table and placing a card face-down on the discard pile. Players can knock when the value of their deadwood reaches 10 points or less. If a player has no cards which do not fit into melds, he or she is “going gin,” and a point bonus may be offered. If all 11 of the player's cards fit into melds, he or she may be permitted to make a big gin, going out without discarding.
The face cards are given a value of 10 points each, while the ace is worth one point, and the numbered cards are worth their face value. Once a player knocks and shows his or her melds, the other player must show his or her melds. If the opponent has cards which will fit into the melds of the player who has gone out, these cards may be “laid off,” attached to the melds of the opponent so that they do not count as deadwood, unless the opponent has gone gin, in which case these cards are treated as deadwood.
Once all of the melds have been shown, the players add the value of their deadwood. The person who knocked receives the difference in deadwood points. For example, if someone knocked with deadwood worth two points and the opponent ended up with deadwood worth 22 points, the knocker would receive 20 points. If the opponent's deadwood is less than that of the knocker, the knocker is said to be “undercut,” and the opponent wins a point bonus along with the difference in the points. The game is over when one player has reached a score of 100, which may take many rounds, or just a few, depending on how the cards play out.
Most of the variations on the gin rummy rules involve the point bonuses. For example, the bonus for undercutting the knocker varies from 10 to 25 points. The bonus for going gin also varies. Players may also have house rules such as a rule which dictates that the starting card in the discard pile must be offered to everyone at the start of the hand, with the person who takes the card starting the hand, unless no one wants it, in which case the player opposite the dealer draws first and begins the hand.