Set Up - Backgammon is a two player game, played on a board consisting of four quadrants of six points (the narrow triangles in the pic below) each of alternating color. In the picture below, the bottom of the image would be towards you, the light player.
The Object of the Game - Your goal is to move your checkers to your home board and then bear them off (remove them from the board). The first player to bear off all their checkers wins the game.
Game Play - In the image above, players would be seated on the side of their home board (light moving counter-clockwise and dark clockwise). To start the game each players throws a single six-sided die. The player rolling the highest number used both throws as their starting rioll. Ties are rolled again.
From then on, each player takes alternate turns, throwing two dice and moving their checkers. Depending on the toss and strategy the player whose turn it is moves either two checkers, each the number of pips shown on one of the dice, or moves one checker wice, once for each die throw. If a player rolls doubles however, the roll is treated as if they threw four dice of the same number! So a roll of 4, 2 would mean either moving one checker 4 points and one 2, or moving one checker a total of 6 in two moves (4 and 2), while a roll of 4, 4 would mean four distinct 4 point moves were available to the player!
Rules of Movement in Backgammon - Movement is dictated by a couple important rules.
- A checker can only be moved to an open point. A point is considered open if it is unoccupied, occupied by the player's own checkers or occupied by only one of the opposing player's checkers. Essentially, if the other guy has two checkers on a point, you can't finish your move on that point.
- Each die represents a distinct move, neither of which can finish on a closed point. In the 4, 2 example above, if the player chose to move one checker the full 6 points, both the move of 4 and the move of 2 would have to end on open points.
- A player throwing doubles plays the throw twice. A roll of 4, 4 becomes 4, 4, 4, 4 to be played in any combination of checkers they see fit, so long as each move lands on an open point.
- If possible within the rules, a player must use both numbers of a roll (or all four in the case of a double). If only one number can be played, it must. If either, but not both can be played, the higher of the two must be played. If neither die represents a possible move, the player loses their turn. With doubles, where all four cannot be played, the player must play as many as possible.
The Rules of Hitting and Entering - If a point is occupied by a single checker (called a blot), an opposing player can finish their move on that point (called a hit) and move their oppenent's checker to the bar (raised middle section of the game board).
A player with a checker on the bar must enter play before making any other moves. To enter, there must be an open point in their oppenents home board equal to one of the dice in their roll. If both dice show an open point, then either may be used for the entering move. If neither die represents an open point, the player loses their turn.
If a player has more than one checker on the bar, each must be entered before any other moves are made. Once a player has entered their last checker from the bar, if there is a die left to play, it must be played as per the rules of movement.
Bearing Off - Once a player moves all their checkers into their home board they may begin bearing off. The six points on the players home board count down 6, 5, 4, 3, 2, 1 towards the outer edge of the board. A player may bear off a checker when it resides on a point rolled.
If there are no checkers on a rolled point, then a checker from a higher point may be moved as normal. If no checkers reside on a higher point the player must remove a checker from the highest occupied point.
Bearing off can only occur while all a player's active checkers reside in their home board. If a checker is hit during this time, it must be moved back the player's home board before bearing off can continue. The first player to bear off all fifteen checkers wins.
Rules of Betting and the Doubling Cube in Backgammon - Backgammon is normally bet on a stake per point basis. The game starts at one point.
A player who feels good about their chances can, at the start of their turn, prior to rolling the dice, propose to double the bet. The other player can agree to the double, also claiming the doubling cube and the right to make the next double offer, or concede the game and lose points equal to the current bet. Subsequent offers to double are called redoubles, and can only be made by the current holder of the doubling cube (it changes hands with each acceptance). There is no limit on the number of times the bet can be doubled and redoubled during a game.
Variants of doubling include:
- Automatic doubles at the start of the game each time the players roll a tie when determining who goes first.
- Retaining possesion of the doubling cube by redoubling immediately upon accepting a double, called a beaver.
- Jacoby Rule, where gammons and backgammons only count as a normal game if neither player has offered to double.
Gammons and Backgammons - At the end of the game, if the loser still has all their checkers on the board, it's called a gammon. In the result of a gammon, the losing player loses twice the doubling cube. A gammoned player that still has a checker on the bar or in the home board of the winner is backgammoned, and loses three times the value of the doubling cube!