Advanced Backgammon Rules
In certain games, a common rule allows ‘beavers’ – this is the right for a player to redouble when offered the doubling cube and keeping the cube instead if giving it back up (However, for this to apply, the redouble must be called before the originally doubling player rolls the dice). If you employ this beaver rule, the stakes of the game can rise spectacularly. When you play online you are usually allowed the option of allowing or disallowing the use of beavers before you begin a game.
The Jacoby Rule
This rule makes gammons and backgammons count for their respective double and triple points if, and only if, the doubling cube has been used at least once in the game. This presents a player with a large lead over the opponent to double , and naturally provides a likely opportunity to bring the game to a quick conclusion, rather than have the player pin his hopes on a gammon or backgammon to see the game drag on to the bitter end.
The Crawford Rule
This rule states that when a player is one single point away from winning a match, neither player may use the doubling cube for a single game, called the “Crawford Game”. As soon as the Crawford Game is over, the doubling cube may be used as normal in further games.
When Automatic Doubles are employed, any re-rolls that players make at the very start of the game (when each player rolls one die) have the knock-on effect of causing a doubling. So, a 3-3 roll, followed by a 5-5 roll, followed by a re-roll of 1-4 that begins the game in earnest, will cause the game to be played from the beginning with 4 times normal stakes. The doubling cube stays in the middle, with both players having access to it.
Automatic Doubles are common in money games (upon agreement). However, they are never used in match play.