Backgammon rules

Backgammon is a two-player game played on a 

board of 24 narrow triangles

 called points. The points are grouped into four quadrants, each containing six points. Each player has fifteen checkers of their own color. The initial arrangement of the checkers is shown in the figure below.

Each side of the board consists of 

12 elongated triangles

 called points. At the start of the game, the checkers are placed on the board in a fixed pattern, shown below.

The 

home board

 is the section of the board that contains a player’s home area. In the image below, White’s home board is highlighted in a lighter shade, while Black’s home board is shown in a darker shade.

The points are 

also numbered

 for reference. The image above shows the first six points numbered for White and Black respectively. Each player’s home board contains points 1 through 6. Black’s 1-point is the same as White’s 24-point.

The two players 

move their checkers

 in opposite directions along a continuous horseshoe-shaped track. Both players move their checkers toward their own home board.

The starting 

player rolls two dice

 (this is done automatically in the game). The numbers rolled indicate how many points the player may move their checkers. Checkers always move forward. The following rules apply:

A point occupied by a single checker of either color is called a 

blot

. If an opposing checker lands on a blot, the blot is hit and placed on the 

bar

.

Whenever a player has one or more 

checkers on the bar

, their first obligation is to enter those checkers into the opponent’s home board. A checker is entered by moving it to an open point corresponding to one of the numbers rolled on the dice.

If neither of the corresponding points is open, the 

player loses their turn

. If a player is able to enter some but not all of their checkers, they must enter as many as possible and forfeit the remainder of the turn.

After the 

last checker

 has been entered, any unused dice numbers must be played by moving either the checker that was entered or another checker.

Once a player has 

moved all fifteen checkers

 into their home board, they may begin bearing off, that is, removing checkers from the board. A roll of 1 may be used to bear off a checker from the 1-point, a roll of 2 from the 2-point, and so on.

To 

bear off

, move the checker off the board from the home board side. The display box shows the checkers already borne off by both players.

A die may not be used to bear off a checker from a 

lower-numbered point

 unless there are no checkers on any higher-numbered points.

A player is 

not required to bear off

 if they can make another legal move.

The 

doubling cube

 can be used in match play to increase the stakes and add strategic depth. At the start of the game, the cube is in a neutral position at the top right corner of the screen.

While the cube is in this neutral position, either player 

may propose doubling

 the current stakes on their turn by clicking the cube.

The opponent 

may accept

 by clicking the cube, 

or decline

 and concede the game immediately.

If the opponent accepts, the 

cube is moved

 next to that player’s name and shows the current stake.

The 

maximum stake

 depends on the number of points required to win the match.

The player who bears off all of their checkers first 

wins the game

.

Match play

 means that the players continue playing until one side reaches or exceeds a 

certain number of points

.

The winner of a single game within a match 

scores 1 point

 if the doubling cube was not used. If the cube was used for doubles or redoubles, the winner scores the number of points shown on the cube.

If the losing player has not borne off any checkers by the time the winner has borne off all 15 checkers, the game is called a 

gammon

, and the score is doubled.

A backgammon occurs when the winner has borne off all of their checkers while the losing player has not borne off any checkers and still has one or more checkers in the winner’s home board or on the bar. In this case, the winner 

scores three times the cube value

.