Backgammon is a game for two players, played on a board consisting of twenty-four narrow triangles called points. The triangles alternate in color and are grouped into four quadrants of six triangles each. The quadrants are referred to as a player's home board and outer board, and the opponent's home board and outer board. The home and outer boards are separated from each other by a ridge down the center of the board called the bar.
Unlike chess it doesn't matter which color checkers the players use as either player has the opportunity to make the first move.
To play backgammon the following equipment is used:
1 backgammon board
30 Checkers - 15 of one color and 15 of another.
2 six-sided dice
2 dice cups for rolling the dice
1 six-sided doubling cube with the numbers 2, 4, 8, 16, 32, and 64 on the 6 faces
The starting position in backgammon is as follows:
Two checkers on each player's 24-point
Five checkers on each player's 13-point
Three checkers on each player's 8-point
Five checkers on each player's 6-point
Object of the Game
The players must move their checkers according to the numbers shown on the dice. Backgammon is played so that you move your checkers in the direction from your opponent's home board to your home board. As soon as all of your checkers are in your home board you can begin to remove checkers from the board (the bear off). You win the game by bearing off all of your checkers first.
To start off a game of backgammon, you and your opponent each throw a single die.
The player with the highest number moves first, using the number from both dice rolled to move his or her checkers.
In case the same number appears on both dice, the players keep rolling their die until the get different numbers.
After the initial move, the opponents alternate turns and roll two dice each time.
Movement of the Checkers
The roll of the dice indicates how many points, or pips, the player is to move his checkers. The checkers are always moved forward, to a lower-numbered point. The following rules apply:
1) A checker may be moved only to an open point, i.e. point that is occupied by your own checkers or to a point that has max one of your opponent's checkers on it. In other words, you may not move a checker to a point where your opponent has two or more checkers.
2) The numbers on the two dice constitute separate moves. For example, if a player rolls 5 and 3, he may move one checker five spaces to an open point and another checker three spaces to an open point, or he may move the one checker a total of eight spaces to an open point, but only if the intermediate point (either three or five spaces from the starting point) is also open.
3) If you roll the dice and the same number comes up on both dice (also called rolling doubles) you may move double the amount shown. Say for example that you roll a double five. Then you may move five points four times, in any possible combination.
4) A player must use both numbers of a roll if this is legally possible (or all four numbers of a double). When only one number can be played, the player must play that number. Or if either number can be played but not both, the player must play the larger one. When neither number can be used, the player loses his turn. In the case of doubles, when all four numbers cannot be played, the player must play as many numbers as he can.
Hitting and Entering
A single checker on a point is known as a blot. Checkers of opposite colors may not inhabit the same point. Because of this a blot is removed if an opponent lands on it (a hit). The checker is moved to the bar.
The middle strip that divides the inner and outer boards makes up the bar. When a checker is placed on the bar, it stays out of play until it's entered in your opponent's inner board. You can re-enter your checker from the bar if the numbers shown on the dice correspond to a point not occupied by two or more of your opponent's checkers.
If you have one or more checkers on the bar, all of these must be re-entered to the board before you may move your other checkers. Should you have any unused numbers on the dice after re-entering your checkers, these may be used to move your checkers on the board.
In case you are unable to enter because the points indicated by the dice, the turn goes to your opponent.
A player who has made all six points in his home board is said to have a closed board. If the opponent has any men on the bar, he will not be able to re-enter it since there is no vacant point in his opponent's home board. Therefore, he forfeits his rolls, and continues to do so until such time as the player has to open up a point in his home board, thus providing a point of rentry. It should be noted, the he doesn't loses his turn, as he still retains the ability to double his opponent before any of his opponents rolls, assuming the cube is centered or on his side.
After the last of player's checkers has been entered, any unused numbers on the dice must be played, by moving either the checker that was entered or a different checker.
Once a player has moved all of his fifteen checkers into his home board, he may commence bearing off. A player bears off a checker by rolling a number that corresponds to the point on which the checker resides, and then removing that checker from the board. Thus, rolling a 6 permits the player to remove a checker from the six point. If there is no checker on the point indicated by the roll, the player must make a legal move using a checker on a higher-numbered point. If there are no checkers on higher-numbered points, the player is permitted (and required) to remove a checker from the highest point on which one of his checkers resides. A player is under no obligation to bear off if he can make an otherwise legal move.
A player must have all of his active checkers in his home board in order to bear off. If a checker is hit during the bear-off process, the player must bring that checker back to his home board before continuing to bear off. The first player to bear off all fifteen checkers wins the game.
Backgammon is played for an agreed stake per point. Each game starts at one point.
During the course of the game, a player who feels he has a sufficient advantage may propose doubling the stakes. He may do this only at the start of his own turn and before he has rolled the dice. A player who is offered a double may refuse, in which case he concedes the game and pays one point. Otherwise, he must accept the double and play on for the new higher stakes.
A player who accepts a double becomes the owner of the cube and only he may make the next double.
Subsequent doubles in the same game are called redoubles. If a player refuses a redouble, he must pay the number of points that were at stake prior to the redouble. Otherwise, he becomes the new owner of the cube and the game continues at twice the previous stakes. There is no limit to the number of redoubles in a game.
The Crawford Rule
The Crawford rule is standard in match play. The rule states that after a player comes within one point of winning the match, the following game is played sans a doubling cube. This particular game is known as the Crawford Game.
Gammons and Backgammons
At the end of the game, if the losing player has borne off at least one checker, he loses only the value showing on the doubling cube (one point, if there have been no doubles). However, if the loser has not borne off any of his checkers, he is gammoned and loses twice the value of the doubling cube. Or, worse, if the loser has not borne off any of his checkers and still has a checker on the bar or in the winner's home board, he is backgammoned and loses three times the value of the doubling cube.
The following optional rules are in widespread use.
Automatic doubles. If identical numbers are thrown on the first roll, the stakes are doubled. The doubling cube is turned to 2 and remains in the middle. Players usually agree to limit the number of automatic doubles to one per game.
Beavers. When a player is doubled, he may immediately redouble (beaver) while retaining possession of the cube. The original doubler has the option of accepting or refusing as with a normal double.
The Jacoby Rule. Gammons and backgammons count only as a single game if neither player has offered a double during the course of the game. This rule speeds up play by eliminating situations where a player avoids doubling so he can play on for a gammon.