"Les bateaux de la Principauté" Backgammon

A game of Backgammon is played between two players. The game takes place on a board with 24 triangles, also known as points, alternating between two distinct colors.

Each player has 15 checkers of their own color, which they move from point to point based on the roll of two dice.

The goal is to move all of your checkers into your home board and then bear them off the board.

The winner is the first to bear off all 15 checkers.

Movement occurs from the opponent's home board to your own home board, with no backward movement allowed for either player.

To determine who starts, each player rolls one die, and the player with the higher roll plays first, using the combined value of both dice. In case of a tie, the roll is repeated, ensuring that no game starts with a double.

Each player moves their checkers according to the numbers rolled, then picks up their dice to signal the end of their turn. Moves are made independently for each die, except in the case of a double, where four moves are made.

A checker can land on an empty point, a point occupied by the player's own checkers, or a point occupied by a single opposing checker, resulting in a hit. (In the event of a hit, the opponent's checker is placed on the bar and must re-enter the game in the opponent's home board.)

A checker cannot land on a point occupied by two or more opposing checkers. A point occupied by two or more checkers of the same player is called a block. The opponent cannot land on or pass through a blocked point but can jump over it. Note: There is no limit to the number of checkers of the same color on a single point.

The bearing-off phase, the final stage of the game, begins once all of a player's checkers are in their home board. Each die allows a checker to be borne off from the corresponding point, unless there is no checker on that point, in which case the player must make another legal move. There are two cases:

Bearing off a checker is not mandatory if it can be replaced by the legal movement of another checker. As before, doubles are played twice (four moves).

The stakes vary depending on the bearing off and the game situation:

If the losing player has not borne off any checkers but has no checkers in the opponent's home board or on the bar, the game is declared a gammon or double, and the winner scores two points (or twice the value indicated by the doubling cube).

If the losing player has not borne off any checkers and still has one or more checkers in the opponent's home board or on the bar, the game is declared a backgammon or triple, and the winner scores three points (or three times the value indicated by the doubling cube).

A checker hit and placed on the bar:

There is no limit to the number of checkers on the bar. A checker on the bar re-enters the game by landing in the opponent's home board (points 1 to 6) based on the roll of the dice: a 1 allows entry on the opponent's 1-point, a 2 on the 2-point, etc., provided the entry point is not occupied by a block. If a player has one or more checkers on the bar, they must re-enter all of them before making any other move. If the dice do not allow this, the player must pass their turn.

The doubling cube:

A six-sided cube (2, 4, 8, 16, 32, and 64) is used to increase the stakes of the game. At the start of each game, the doubling cube is placed on the bar or the side of the board, indicating that the game's stake is one point. To double the stake, a player must wait for their turn and do so before rolling the dice. They then present the cube to their opponent with the top face showing the value 2, saying "I double" or an equivalent phrase.

Its use can be accepted or declined by the opponent, affecting the course of the game.

Later in the game, the player who accepted the double becomes the owner of the cube and is the only one who can redouble to 4, following the same procedure as the initial double. If the redouble is accepted, the new owner will be the only one able to redouble to 8, and so on.

The match:

A match is played until one player reaches a predetermined odd number of points. Points are awarded at the end of each game based on the results, and the first player to reach the required number wins the match, following the Crawford rule.

This rule states that if one player is one point away from winning, the doubling cube cannot be used in that game.