The Doubling cube

Doubling cube is used to up the stakes during a backgammon game. This fairly recent addition to backgammon takes this game to the next level by adding a whole new dimension of strategy to the game. Handling the doubling cube well is vital, because using it right can literally double ones earnings.

How the doubling cube is used

Backgammon is often played in matches, where a certain amount of points has to be won to win the match. Each game is worth one point at the beginning and a new game is played if neither player reached the number of points needed to win the match.

So, each backgammon game is worth one point in the beginning. On his turn a player can double this amount, and if the opponent accepts, the game will continue. Now the game is worth two points (double the previous amount) and now the player who accepted the double is the one who may double. This is the standard way how the doubling cube is used.

Detailed instructions

If neither player has yet doubled in a game, then either player may use the doubling cube to double the point value of the game. Player announces a double at the beginning of his turn, before he rolls the dice.

Opponent has to either accept the double or concede the game. If the opponent concedes, the doubling player wins as many points, as the game was worth before the doubling was offered.
Player accepting a double gets control of the doubling cube and is the only one who can now double. Player controlling the doubling cube can double anytime he wants when it is his turn (again before he rolls the dice). If he doubles, the other player must concede or accept, and if he accepts he again gets the control of the cube.

The doubling cube has numbers 2, 4, 8, 16, 32 and 64, but there is no limit to the doubling, so theoretically game can be doubled to 128, 256, etc. However in real life it is rare to see a game doubled beyond 4.

Beavers and other optional rules

Beaver is an often used addition to the doubling cube rules. Beaver means that a player who is deciding wheter to accept a double or not, may immediately redouble and keep control of the cube! So if an opponent makes a poorly calculated double to 2, his opponent may immediately “beaver” to 4 and keep control of the doubling cube (and probably double again to 8 a little later…)

Another optional rule that deals with doubling cube is the Crawford rule. It states that when after a game either one of the players is one point away from winning (i.e. 4-3 in a five point match), then the next game is played without the cube. See full explanation of the Crawford rule for more information.

Winning, gammons, backgammons and the doubling cube

When a game ends, winning player gets as many points as is the value shown on the doubling cube. This number is multiplied by two for gammons and three for backgammons. So if doubling cube is at 4 and player wins a backgammon, he gets 3×4 = 12 points.