Overview
Backgammon is a game of luck and skill that is played by two people with 15 checkers each on a board consisting of 24 spaces or points. The checkers are moved according to rolls of the dice. Each player tries to bring his own checkers home and bear them off before his opponent does, hitting and blocking the enemy checkers along the way.

Setup
Backgammon is a game for two players, played on a board consisting of twenty-four narrow triangles called points. The triangles alternate in colour and are grouped into four quadrants of six triangles each. The quadrants are referred to as a player's home board and outer board, and the opponent's home board and outer board. A ridge down the centre of the board called the bar separates the home and outer boards from each other.

The points are numbered for either player starting in that player's home board. The outermost point is the twenty-four point, which is also the opponent's one point. Each player has fifteen checkers of his own colour. The initial arrangement of checkers is: two on each player's twenty-four point, five on each player's thirteen point, three on each player's eight point, and five on each player's six point.

Both players have their own pair of dice and a dice cup used for shaking. A doubling die, with the numerals 2, 4, 8, 16, 32, and 64 on its faces, is used to keep track of the current stake of the game.

Object of the game
The object of the game is for a player to move all of his checkers into his own home board and then bear them off. The first player to bear off all of his checkers wins the game.

Movement of checkers
To start the game, each player throws a single die. This determines both the player to go first and the numbers to be played. If equal numbers come up, then both players roll again until they roll different numbers. The player throwing the higher number now moves his checkers according to the numbers showing on both dice. After the first roll, the players throw two dice and alternate turns.

Except for the very first roll, the beginning of a player’s turn will cause a drop down panel to appear with two options:

• USE DOUBLER: Using this option will give the opponent an offer to double. Read the section on doubling for more details. This option will be disabled if you cannot double at this time.
• ROLL DIES: This will roll your two dies and cause the movement phase to begin.

The roll of the dice indicates how many points, or pips, the player is to move his checkers. The checkers are al-ways moved forward, to a lower-numbered point. The following rules apply:

• A checker may be moved only to an open point, one that is not occupied by two or more opposing checkers.
• The numbers on the two dice constitute separate moves. For example, if a player rolls 5 and 3, he or she may move one checker five spaces to an open point and another checker three spaces to an open point, or he may move the one checker a total of eight spaces to an open point, but only if the intermediate point (either three or five spaces from the starting point) is also open.
• A player who rolls doubles plays the numbers shown on the dice twice. A roll of 6 and 6 means that the player has four sixes to use, and she or he may move any combination of checkers she or he feels appropriate to complete this requirement.
• A player must use either numbers of a roll if this is legally possible (or all four numbers of a double). When only one number can be played, the player must play that number. Or if either number can be played but not both, the player must play the larger one. When neither number can be used, the player loses his turn. In the case of doubles, when all four numbers cannot be played, the player must play as many numbers as he can.

Players can move their checkers by dragging them to a new point, but only if a small dot appears over the checker when the mouse cursor is above it. Small triangles will appear whenever a checker is picked up, each indicating a legal move with this checker. If the checker is green, the move is forward, if the checker is red it is an undo move. If the checker is dragged to an illegal point, a cross will appear over the checker, and if the checker is dropped here, it will snap back to the previous point.

Once a player has made all the possible moves this turn, a drop down panel will appear with the following buttons:

• UNDO MOVES: This will cause all the moves this turn to be undone and the player will be allowed to spend his dies again.
• SEND MOVES: When this button is pressed the moves made this turn will be sent to the opponent who will then have the turn.

Hitting and entering
A point occupied by a single checker of either colour is called a blot. If an opposing checker lands on a blot, the blot is hit and placed on the bar. Dragging a checker over an opposing blot will cause a star to appear over the checker indicating it will be hit if the player drops his or her checker there.

Any time a player has one or more checkers on the bar, his first obligation is to enter those checker(s) into the opposing home board. A checker is entered by moving it to an open point corresponding to one of the numbers on the rolled dice.

For example, if a player rolls 4 and 6, he may enter a checker onto either the opponent's four point or six points, so long as the prospective point is not occupied by two or more of the opponent's checkers.

If neither of the points is open, the player loses his turn. If a player is able to enter some but not all of his checkers, he must enter as many as he can and then forfeit the remainder of his turn.

It is not possible to move any other checker before all of the player’s checkers have been entered.

After the last of a player's checkers has been entered, any unused numbers on the dice must be played as usual.

Bearing off
Once a player has moved all of his fifteen checkers into his home board, he may commence bearing off. A player bears off a checker by rolling a number that corresponds to the point on which the checker resides, and then re-moving that checker from the board. Thus, rolling a 6 permits the player to remove a checker from the six points.

If there is no checker on the point indicated by the roll, the player must make a legal move using a checker on a higher-numbered point. If there are no checkers on higher-numbered points, the player is permitted (and required) to remove a checker from the highest point on which one of his checkers resides. A player is under no obligation to bear off if he can make an otherwise legal move.

A player must have all of his active checkers in his home board in order to bear off. If a checker is hit during the bear-off process, the player must bring that checker back to his home board before continuing to bear off. The first player to bear off all fifteen checkers wins the game.

Doubling
Backgammon is played for an agreed stake per point. Each game starts at one point. During the course of the game, a player who feels he has a sufficient advantage may propose doubling the stakes. He may do this only at the start of his own turn and before he has rolled the dice.

A player who is offered a double may refuse, in which case he concedes the game and pays one point. Other-wise, he must accept the double and play on for the new higher stakes. A player who accepts a double becomes the owner of the die and only he may make the next double.

Subsequent doubles in the same game are called redoubles. If a player refuses a redouble, he must pay the number of points that were at stake prior to the redouble. Otherwise, he becomes the new owner of the die and the game continues at twice the previous stakes. There is a fixed limit to the number of redoubles in a game of five, resulting in a value of 64.

Gammons and backgammons
At the end of the game, if the losing player has borne off at least one checker, he loses only the value showing on the doubling die (one point, if there have been no doubles). However, if the loser has not borne off any of his checkers, he is gammoned and loses two times the value of the doubling die. Or, worse, if the loser has not borne off any of his checkers and still has a checker on the bar or in the winner's home board, he is backgammoned and loses three times the value of the doubling die.

Match types
A game of backgammon can be played over one round or over multiple rounds to a predetermined number of backgammon points. Playing just one round will have the doubling die disabled throughout the match. A point match will usually run over more than one round because of the point goal and not individual game wins. The point goal could be set to 2 or 5 or even more points. A number of rounds will have to be played until the set number of points is reached.

Crawford rule
The first time either of the players reaches match point (reaching 4 points in a 5 points match), the Crawford rule states that the next round will be played without the doubling die. This rule can be enabled or disabled in the game settings in the matchmaking lobby.