The Crawford Rule

Almost every backgammon tournament, live or online, plays matches with the Crawford rule. Online servers often let you switch it off for casual matches, but it is on by default. Here is what it says and why it makes sense.

The rule

When one player reaches a score that is one point short of winning the match, the next game is played without the doubling cube. Neither player may double in that one game, which is called the Crawford game.

For example, in a 9-point match a player who goes ahead 8-6 has reached "match point minus one." The next game is the Crawford game. If the leader wins it, the match is over. If the trailing player wins it, the score might become 8-7 or 8-8, and from the following game onward the cube is back in play. These later games are called post-Crawford games.

The Crawford game happens only once per match. If the leader reaches 8 points and the trailing player later also reaches 8, there is no second Crawford game.

Why the rule is needed

Without the rule, matches would end with some strange cube action. Look at two cases in a 9-point match.

Case 1: the trailing player has nothing to lose

The score is 8-6. The leader needs one more game. Without the Crawford rule, the trailing player would double on his first turn every time. Losing a doubled game costs him nothing extra, because any loss already ends the match, and winning a doubled game is worth two points to him. The leader's hard-earned position would be worth much less.

Case 2: a double that changes nothing

The score is 5-6 and the player with 5 doubles. Without the Crawford rule, the leader could take with almost any position, unless he is in danger of losing a gammon. If he loses the doubled game, the score becomes 7-6, and the player at 7 would then face an automatic double at the start of the next game. Getting to two points from victory would have gained him almost nothing.

By guaranteeing one game without the cube, the Crawford rule gives real value to getting close to the end of a match.

Why not simply ban doubling for the rest of the match?

A simpler rule might seem to be: once anyone is one point away, no more doubling. But that would be very unfair to the trailing player. At 8-4 in a 9-point match, he would need to win five games in a row with no way to raise the stakes. With the Crawford rule, he must win the Crawford game, but after that he can double and play for two points a game. A comeback is still hard, but it is possible.

Strategy after the Crawford game

In post-Crawford games, the trailing player usually doubles at his first chance, because for him a doubled game is worth two points and a loss ends the match anyway. The leader, who has nothing to gain from the cube, normally takes. One small exception exists when the trailing player needs an even number of points, such as 2 or 4, which gives the leader one "free drop": he can pass a double once without hurting his chances, an idea worth studying once you start playing matches regularly.

Final thoughts

The Crawford rule is not perfect, but it is a good compromise. It rewards the player who gets close to winning while leaving the trailing player a fair fighting chance. If you can choose, play with it. For more on the cube, read our articles on the doubling cube, the Jacoby rule, which is used in money play instead, and backgammon tournaments.