The standard rules of 1931 worked well and were widely adopted in North America and to a lesser extent in Europe. But as backgammon began to resurge in popularity in the late 1960s, the rules were in need of updating. The goal was to clarify some aspects of the game which were not clear in the older rules and to delete certain optional rules that were no longer used.
These rules were prepared by the International Backgammon Association and were in force at the annual tournaments held at Grand Bahama Island and at Las Vegas in the 1960s. They were published in Obolensky's and James's popular book Backgammon: The Action Game. Oswald Jacoby and John Crawford published a similar set of rules around the same time.
Differences from the 1931 rules are relatively minor. A procedure is given for determining who gets which seats, checkers, and dice. The terminology is updated slightly: "throwing off" is now "bearing off"; "inner table" is now "home board"; "doublets" are now "doubles." Touch rules are relaxedyou are now allowed to take back a move as long as you haven't picked up the dice.
Some rules were deleted: A rethrow is no longer required if a player picks up his dice prematurely (probably a good idea). The optional scoring method of one point for each checker still on the board is no longer included.
IBA LAWS OF BACKGAMMON
- The game is played by two people.
- Play of the men is governed by two dice, thrown (cast) from a cup in which the dice are shaken before casting.
- For the first game, either player may ask to roll for choice of seats, men, dice. Otherwise, they just sit down, set the men up, and play.
- At the start of any later game, either player may ask to mix the dice. In this case, he shakes the four dice together in one cup and rolls them out. The opponent selects a die, then the roller, then the opponent, with the roller taking the last one.
- For the opening throw each player throws a single die. Every tie requires another opening throw. Whoever throws the higher number wins, and for his first move plays the numbers upon both dice. After that, each player in turn throws two dice.
- The dice must be rolled together and come to rest flat (not "cocked") upon the tables at
the player’s right, otherwise they must be thrown again.
- There must be a rethrow if a throw is made before an adversary's play is completed or if either player touches a die before it comes to rest.
- A play is deemed completed when a player moves his men and starts to pick up his dice. If he starts to pick them up before playing all numbers he legally can, his opponent has the right to compel him to complete or not to complete his play. A roll by the opponent is an acceptance of the play as made. (See rule sixteen.)
- The play of the men consists in:
- moving a man (or men) the exact number of points indicated by the number on each of the two dice thrown;
- entering a man, in the adversary’s inner table, on a point corresponding to the number on a die thrown;
- bearing off a man in player’s home board, when no man is left outside that board or on the bar, in accordance with rule fourteen.
- Doublets require four plays of the number on the dice.
- Plays must be made for both dice if possible. Either number may be played first. If either number thrown may be played, but not both, the the higher number thrown must be played.
- No play may be made which lands on a point held by two or more of the opponent’s
- When a play lands on a point occupied by a single man of the opponent's, such a man is hit and must be lifted from the board and placed on the bar for entry in accordance with rule eight.
- A player having a man on the bar may not play any other man until that man has entered.
- When in a position to bear off, you may bear off a man from a point corresponding to the number on a die thrown or from the highest occupied point which is lower than the number indicated by a die. If a number is thrown for an unoccupied point, no man below can be borne off, for such number, while any man remains on a higher point. You are not required to bear off a man if you are able to move a man forward on the board. Rule ten applies here as in all other situations.
- If an error has been made in the setup it must be corrected if either player notices it before the second play of the game has been completed.
- If an error in play has been made, either player may require its correction before a subsequent throw, but not thereafter.
- A game is won by the player who first bears off all of his men.
A gammon (double game) is won if the adversary has not borne off a single man. This
doubles the count.
A backgammon (triple game) is won if the adversary has not thrown off a single man, and has one or more men in the winner’s inner table or upon the bar. This triples the count for a single game.
- Doubling game. The count is raised:
- Automatically: Each tie of the opening throw doubles the previous count. Unless an understanding has been reached as to the method and limitation of automatic doubles they are not played.
- Voluntarily: Either player may offer the first optional double of the previous count. After that, the right to double the previous count alternates, being always with the player who has accepted the last double.
In every case, a double may be offered only when it is the player’s turn to play and before he has thrown the dice. A double may be accepted or declined. The refusal of a double terminates the game, and the player refusing loses whatever the count may amount to before the double was offered.
|Differences from Present-Day Rules|
- Rule 16 says that either player may require the correction of an error in play. Present-day rules are that it is solely the opponent's option whether or not to correct a play.
- Two additional rules are in widespread use today:
The Jacoby rule, which says that the winner only scores extra for a gammon or backgammon if the cube has been turned.
Beavers, which allows a player who has accepted a double to immediately redouble without giving up ownership of the cube.