The California rule in the Chouette game

Any rules should be agreed before play begins to ensure that all players are prepared for their Chouette game. The California rule states that, at the beginning of the Chouette game, the backgammon player that wins the opening roll has the option of turning the cube to level two and re-rolling both the backgammon dice. The cube must also stay in the middle.

Many backgammon players believe that if the player scores a natural 3-1, 4-2 or 6-1, they should accept this roll and continue play. If any other amount is rolled, then they should play the California rule, turn the cube and re-roll the dice. However, backgammon strategy and statistics suggest that if the California rule is played during a Chouette game, then the players should always choose to turn the cube and re-roll both dice rather than continue with their initial roll, even if an initial 31 was scored.

This is because the chance of throwing any of the possible doubles is high. Also, the doubling of the cube at this point gives you an advantage in the Chouette game. At this stage, the backgammon player does not forsake cube access when increasing the stakes.

The reasoning behind this approach is that the equity on a Chouette opening roll with permitted doubles on a 1-cube is 0.061. Therefore, the equity on the same roll using the California rule with a level 2 cube is 0.122. Therefore, the equity is greater than any non-double opening rolls on a 1-cube. This includes an opening roll that scores 31.