Cutthroat is a version of Gin Rummy designed for three players, but only two players are active at one time. This is also known as Round Robin Gin Rummy.
To determine the first two participants, all three players draw a card from the deck. The player drawing the lowest card sits out the first round. The holder of the second-lowest card becomes the dealer, and plays against the holder of the highest card. After the first hand, the loser of the hand sits out, and the idle player deals to the winner. The idle player may only observe, and not offer advice to either active player.
Each player plays for himself, with a running total score kept for all three. The first player who reaches 100 points is the winner of the game. After game and box bonuses have been added (100 bonus points for the game, 25 points for each hand won), each player pays the difference in score to his opponents. If a player is shut out, he pays an additional 100 points to the winner of the game. The winner collects from two players; the second-place finisher collects from one player and pays to one player, and the overall loser ends up paying to the two other players.