Backgammon is a very old game played with many different rule sets. These are the rules used online and offline in competitive backgammon.
Object of The Game
Backgammon is a two player game. The player who first moves all his checkers to his home board and then removes them from the board wins. Backgammon can be played in matches, where a certain score has to be reached to win it, or as single games.
Set up
Checkers (15 per player) are placed on the 24 triangles (”points”) as in the picture below.
In addition to checkers and the board, dice and a doubling cube (optional) are used. Both players have their own dice.
Moving the checkers
Beginning player is chosen by each player throwing one die. In case of a tie the dice are thrown again, until no tie happens. Player who threw the higher number starts by using the die rolls used to determine the beginning player.
After the first turn, players throw two dice and alternate taking turns.
The dice control how many points a player must move his checkers. Checkers are always moved forward, towards the players own home board. Die rolls move checkers exactly the number of points equal to the number shown on the die (ie. six can not be used to move checker just four points).
Die rolls can be used to either:
Move two different checkers. One for each die.
or
Move one checker two times. In this case the die rolls are not added. For example rolling three and four moves the checker three and four points or four and three points, but not single leap of seven points.
Double rolls are used twice. For example rolling 4 and 4 allows the player to move his checkers 4, 4, 4, and 4 points.
Checker can be moved to an open point or to a point where player has his own checkers. There is no limit to how many checkers single point can hold.
Checker can be also moved to a point where opponent has exactly one checker (lone checker is called a “blot”). This move is called hitting. Opponent’s checker is removed from the point and placed to the middle of the board (see “hitting and entering”).
Checker can not be moved to a point where opponent has two or more checkers.
No voluntary passing is allowed.
All die rolls must be used if possible.
If only one die roll can be used, it must be used.
If either higher or lower of the dice can be used, then the bigger number must be used.
If no moves can be made, then the player must pass.
Hitting and Entering
Hitting a blot: If player places his checker to a point occupied by exactly one of opponents checker, the opponents checker is placed to the middle of the board (the “bar”).
If player has one or more checkers at the bar, he must enter all of them back to the game, before he can do anything else. Checkers are entered to the opposite color’s home board (ie white enters on black’s home board and vice versa). Checker is entered by placing it to a point corresponding to one of the numbers rolled.
If player has just one checker on the board and can enter it, then he can (and must) use the other die roll normally to move his checkers.
If player has two or more checkers, he enters as many as he can of them back to the board on his turn. After he has entered all of them back to the board, he can start playing normally. Example: player has two checkers on the bar. On his turn he can enter only one of them, so on this turn he cannot do anything else but enter the one checker.
Bearing off
Bearing off is removing checkers from the board. Player may begin to bear off his checkers from the board as soon as he has moved all his 15 checkers to his home board.
Players bear off their checkers by removing them from the rows corresponding to the die rolls. For example by throwing three and four, player may remove checkers from third and fourth point (counting from the edge of the board).
If there is no checker at the point indicated by the roll, player must use the throw to move his checkers forward. If there are no checkers at the point indicated by the roll or farther away, player may bear off one of his checkers farthest from the board’s edge.
Player who first bears of all his fifteen checkers wins the game.
There are three ways to win:
Normal
If player loses and has managed to bear off at least one checker, he loses the value the game was worth at its end - either one or the number shown on the doubling cube (see doubling cube rules).
Gammon
If player loses and did not manage to bear off any checkers, he loses twice the value of the game.
Backgammon
If player loses and has a checker on the bar or at winner’s home board, he loses three times the value of the game.