Jacoby Rule

Jacoby Rule is one of the backgammon rules, used in money games, i.e. backgammon games played individually (not necessarily real money backgammon games), in which players bet on the outcome, as opposed to match games. Money backgammon games can be played for real or for fun money; at the end of each game, the losing player pays the winner the initial stake multiplied by by 2, if the game ended in a gammon or multiplied by 3, if it is a backgammon. According to Jacoby Rules, if a backgammon for money was played without the doubling cube, gammon and backgammon would have been counted as a single win, so the score is one point, multiplied by the final value of the doubling cube.

Jacoby Rule is not in use in match games, which is the most common type of play in backgammon tournaments as well as in online backgammon websites. In match play, the participants play a series of successive games until either player achieves a set number of points. Instead of the Jacoby Rule, backgammon matches use the Crawford Rule, according to which, when one of the players is missing one point to win the match, the use of the doubling cube is forbidden in the following game.

The Jacoby Rule is named after its creator, the famous bridge and backgammon player Oswald Jacoby who won the 1972 World Backgammon Championship. The object of the rule is to speed up the play by limiting the players' possibilities. For example, the dilemma whether to play for the gammon becomes irrelevant once the Jacoby Rule is used.