How to play
Rules
Backgammon is a race for two: each side brings its 15 checkers home and then off the board, and the first to bear them all off wins. These are the rules the table enforces, in the order a game runs.
In short
- Each side has 15 checkers, and moves them round the board toward its home board of 6 points.
- Each number of a roll moves one checker that far. A double is played four times.
- Two checkers make a point the opponent cannot land on; one alone is a blot, and can be hit to the bar.
- With every checker home, a side bears them off. The first with none left wins.
- Before a roll, the side on turn may double the stakes. The other takes, or drops and loses.
- A gammon is worth 2 times the cube, a backgammon 3. A match is played to a set number of points.
The board
The board has 24 points, in four quarters of six, and a bar down the middle. Each side counts the points from its own home board: its 1-point is the last before bearing off, and its 24-point the farthest back. A side starts with two checkers on its 24-point, five on its 13, three on its 8 and five on its 6, and moves from the 24 toward the 1. Its home board is its points 1 to 6.
Who starts
Each side throws one die. The higher moves first, playing the two dice as its roll. A tie is thrown again. After that the turns alternate, and each starts with a throw of both dice.
Moving
Each number of the roll moves one checker that many points forward. One checker may take both numbers, one after the other, if the point between is open. A double is four moves of the number. A checker may land on an empty point, on its own side's, or on a point with one checker of the opponent's, but never on a point the opponent holds with two or more.
Using the roll
A side must play both numbers if any way of playing them does, even if that is not the play it would choose. If only one can be played, it plays that one; if either could be played but not both, it plays the higher. A roll with nothing to play passes the turn.
Hitting and the bar
A checker alone on a point is a blot. An opponent's checker that lands on it hits it, and it goes to the bar. A side with a checker on the bar must bring it in before anything else moves, onto the opponent's home board: a 1 enters on the opponent's 1-point, which is its own 24, a 6 on its 19. A roll that cannot bring every bar checker in plays what it can, and the turn passes.
Bearing off
Once all 15 of a side's checkers are in its home board, it may bear them off: a number takes a checker off from the point of that number. A higher number may bear off from the highest point a checker is on, but not from a lower one while a higher point is held. A checker hit while bearing off has to come all the way home again before any more are borne off.
The doubling cube
A game starts with the cube in the middle, worth one. Before its roll, the side on turn may double. The other side then takes, and owns the cube at twice the value, so that only it may double next; or drops, and loses the game at the value before the double. A side may only double when the cube is in the middle or its own.
Winning a game
The first side to bear off all 15 checkers wins the game and scores the cube's value. If the loser has borne off none, it is a gammon, worth 2 times the cube. If the loser has borne off none and still has a checker on the bar or in the winner's home board, it is a backgammon, worth 3 times.
Resigning
At any moment but while a double waits for its answer, either side may offer to resign: to lose the game as a single game, a gammon or a backgammon, times the cube, though never by more than the game can still be lost by. The other side accepts, and the game ends at that score; or rejects, and the game goes on where it stood. A side whose offer was rejected may offer again once a roll has been played.
Match play
A match is played to 1, 3, 5 or 7 points, game after game. The game after either side first comes within one point of the match is the Crawford game, and nobody may double in it; in the games after it the cube is back. A side is not offered the cube once its value already wins it the match, since doubling then could only cost it. A one-point match is a single game and has no cube.
Writing a move
A play is written from the mover's side, one step a checker: 13/7 is a checker from the 13-point to the 7-point, bar/22 one coming in from the bar, 6/off one borne off, and a star marks a hit, as 18/16*. The table writes the opponent's last play this way.
Long nardi
Long nardi is played on the same board, with the same dice and fifteen checkers a side, and is another game: nothing is ever hit, and the struggle is to block the opponent's way. The table plays it by these rules.
The start
Each side starts with all 15 of its checkers on one point, its head: its own 24-point, which is the opponent's 12. The two heads are in opposite corners. Both sides move the same way round, from the head toward a home board of 6 points just before the opponent's head, so each side's first half of the board is the other's second.
Who starts
Each side throws one die, and the higher starts, throwing both dice for its first turn. A tie is thrown again.
Moving and blocking
Each number moves one checker, and a double is four moves, as in backgammon. But a single checker holds a point: nothing may land where the opponent has a checker, and nothing is ever hit, so there is no bar.
The head
Only one checker may leave the head in a turn. The exception is a side's first turn: with 6-6, 4-4 or 3-3, two may leave, because a single one would run into the opponent's head.
Six in a row
A side may not hold 6 points in a row unless at least one of the opponent's checkers is already past them, since nothing could ever cross such a wall. A play that would leave one is not allowed.
Using the roll
As in backgammon: both numbers if any way of playing them does, the higher when only one of the two can be played, and a roll with nothing to play passes the turn.
Bearing off and winning
A side bears off once all its checkers are home, by the same rules as backgammon. The first to bear off all 15 wins a point; if the loser has borne off none, it is a mars, worth 2. There is no doubling cube, and a match adds these up.