Gin Rummy is a variation on the traditional Rummy game but with some slight variations of the rules. Each player is dealt 10 cards. The dealer puts the rest of the cards in a pile and flips the first card. The point of the game is to get sequential runs of cards in the same suit -- such as a three, four and five of clubs -- or a set, which is four cards with identical rank and different suits. Once you have a set or run in your hand, or a combination of the two that fills you hand, you tap out. The game is then scored.
Count the total value of each card in your hand that is not part of a run or set. Number cards are worth their number value. Face cards are worth 10 and an ace is worth one point.
Count the knocker (the person who knocked the table when they had a satisfactory run). A knocker is allowed to knock on the table when he has 10 points or less of cards that are not part of a set or run. These cards are called deadwood. A player knocks when he believes he will not get rummy (all of the cards in his hand are in a set or run). If the knocker did not go gin but his score when counting the unmatched cards is higher than the opponent, he is undercut (meaning he has more deadwood points than his opponent). The opponent of the knocker gains the difference between the two players card value plus 10 points.
Score a player that goes gin (the entire hand is made of sets or runs) 20 points plus the point value of all unmatched cards in the opponents' hands.
Add a 20-point bonus to the player who wins a hand. Continue playing the game until one person has a cumulative score of 100 or more. Whoever receives 100 first receives a 100-point bonus. If the opponent did not score during the game at all, the person who reaches 100 gets 200 instead of a 100-point bonus