Backgammon Dictionary

A completed game of backgammon in which the losing player has not borne off any checkers. A gammon is also called a double game because the winner receives twice the value of the doubling cube.   Compare: Single Game and Backgammon (2). In money play, with the Jacoby rule in effect, gammons do not count if the doubling cube has not been turned that game.

The minimum number of pips a player needs to roll to bring all his checkers home and bear off his first checker, thereby avoiding losing a gammon.  Compare: Pip Count.

Jacoby rule.

A situation in match play where losing a gammon has no cost, but winning a gammon is particularly valuable. Examples: (a) you trail 4-away/2-away and opponent owns the cube at 2; or (b) you trail 2-away/1-away in the Crawford game; or (c) you trail 3-away/1-away after the Crawford game and the cube is at 2. Gammon-go for you is gammon-save for your opponent. See posts by Mary Hickey and Marty Storer.

A position that has a higher than normal gammon rate.

The relative value of winning a gammon compared with the value of winning a single game. Gammon price is computed as GP = (WG - W) / (W - L), where WG = value of winning a gammon, W = value of winning a single game, and L = value of losing a single game. In money play, the gammon price is 50%. In match play, the gammon price depends on the score of the match and the level of the doubling cube. See posts by David Montgomery and Ron Karr.

The chance of a game ending in a gammon or a backgammon (2) if played to completion (i.e., without a doubling cube). Gammon rate may refer to a particular game in progress or to backgammon games in general. An individual player's gammon rate is the fraction of his wins which are gammons or backgammons. See post by David Montgomery.

A situation in match play where winning a gammon has no value, but losing a gammon is particularly costly. Examples: (a) you lead 2-away/4-away and own the cube at 2; or (b) you lead 1-away/2-away in the Crawford game; or (c) you lead 1-away/3-away after the Crawford game and the cube is at 2. Gammon-save for you is gammon-go for your opponent. See posts by Mary Hickey and Marty Storer.

The additional equity resulting from the possibility of winning a gammon.

The space or spaces between made points.

Gammon-go.

A position from which a player cannot lose.

A Middle Eastern game in which a single checker controls a point (1) and doubles are very powerful.  See: How to Play Gioul.

A roll of 5-5 (double 5's).

Double.

A statement made by a player in a chouette that he is willing to pay the captain or any other team member the full stake at which the game currently stands for the right to take over their games. The player making this offer does so because he wishes to double the box when the other players to do not.

A neural-net computer program that plays backgammon (1) and analyzes positions and matches. GNU Backgammon is a cooperative effort of many volunteers. It is "free" software as defined by the GNU General Public License. See the post by Gary Wong and the tutorial by Albert Silver.  Website: GNU Backgammon.

The opponent's five-point, the best place to build an anchor.

To achieve the points (4) necessary to win a match.

A mode in some computer programs and on some backgammon servers where the computer will automatically bear off the maximum number of checkers possible.