Page "Backgammon" Paragraph 19

Some players may opt to invoke The Murphy rule or the " automatic double rule.

" If both opponents roll the same opening number, the doubling cube is incremented on each occasion yet remains in the middle of the board, available to either player.

The Murphy rule may be invoked with a maximum number of automatic doubles allowed and that limit is agreed to prior to a game or match commencing.

When a player decides to double the opponent, the value is then a double of whatever face value is shown ( e. g. if two automatic doubles have occurred putting the cube up to 4, the first in-game double will be for 8 points ).

The Murphy rule is not an official rule in backgammon and is rarely, if ever, seen in use at officially sanctioned tournaments.