The doubling cube is a strategic tool in backgammon, used to increase the stakes of a match. It’s a special die marked with 2, 4, 8, 16, 32, and 64. A player may offer a double only at the start of their turn, before rolling the dice. The opponent can either accept the double and continue playing for the higher value, or decline and forfeit the game at the current value. Once accepted, the cube passes to the opponent, who then holds the exclusive right to offer the next double.

In match play, the Crawford rule comes into effect when a player reaches one point away from winning the match. During the Crawford game—the next game—the doubling cube cannot be used. After that game, normal doubling resumes.

In backgammon, a player wins 3 points when they win a backgammon. This happens when:

• The losing player has not borne off any checkers,

• And still has a checker on the bar or in the winner’s home board when the game ends.

This is the most severe kind of loss in backgammon and scores three times the current value of the doubling cube (or 3 points if no cube is in play).