Aside from the board, other tools backgammon players, online and offline, use to play the game are the dice, the checkers, and the doubling cube. The doubling cube is marked on six sides with numbers 2, 4, 8, 16, and 64. Players take turns rolling the dice prior to the start of the game to determine who gets the first throw. The player with the higher number in the trial throw starts the game. According to the number that the throw of the dice yields, a player also gets to move his checkers.
1. The rule that commonly applies in free online backgammon games is the Crawford rule. It stipulates that there will be no doubling when a player needs a single point to win the match. For instance, if a player is one point short of a win in a best-of-seven match, he is not allowed to double the dice. While this may seem unfair to the player, it works to the advantage of his opponent.
2. The rule applicable to online backgammon games for cash is the Jacoby rule. Prior to the game, both players agree that back gammons and gammons will qualify for just one point if doubling did not take place during the game.
3. If a player has been doubled, he is given the chance to redouble. The player who beavers or accepts the redoubling takes possession of the dice.
4. Players can agree to double the stakes anytime during a game prior to rolling the dice. Players are not allowed to double during the first round.
5. In online backgammon, a player can demand, when his turn comes and before he rolls the dice, that the stakes be raised. If the other player refuses, he has to quit the game at once. If he accepts, the right to redouble belongs to the player who accepted the double and the cube is placed facing upward showing the power of two to indicate that the game is doubled.