A gammon or backgammon game can only be scored if the cube has been doubled. Used principally in money games and not match play. page top page top page top

There cannot be a gammon or backgammon until there is has been a doubling.

The Jacoby Rule means that gammons and backgammons will count for double and triple points only in the case that at least one doubling has occurred during the game.

Players can agree before the game begins that gammons and backgammons will only count as 1 point if the cube has not been doubled by a player during the course of the game.

Named for Oswald Jacoby, a rule never used in match play and almost always in money play and Chouettes. If the cube has not been turned, the winner cannot score a gammon or backgammon. This rule eliminates situations where a player postpones doubling because he has a small chance of a gammon; it encourages him to double, the opponent drops, and they get on to the next game.

Used with Gammon Cube, named for Oswald Jacoby An regulation that reduces gammons and backgammons' score to a single game if neither player had offered a double.

This rule states that if neither player has offered the doubling cube during the game, there cannot be a gammon or backgammon.

If jacoby rule is in effect, gammons and backgammons are not worth anything in a non doubled game.

If neither player has accepted a Double during a game, then Gammons and Backgammons count as 1 point only, if you decide to play using the Jacoby Rule.

A rule mostly used in money play which disallows gammons and backgammons unless either player has accepted a double during the game. Attributed to Oswald Jacoby.