Classic Backgammon

Move all your checkers around the board and bear off all your pieces from the board before your opponent!

Two game’s mode:

• Play against a friend locally
• Challenge the computer

Backgammon is a two-player board game played with counters and dice on tables boards. It is the most widespread Western member of the large family of tables games, whose ancestors date back nearly 5,000 years to the regions of Mesopotamia and Persia. The earliest record of backgammon itself dates to 17th-century England, being descended from the 16th-century game of Irish.

Starting

Pieces can only move in one direction - from the opponent's inner table through the opponent's outer table, back through the player's outer table and finishing in the player's inner table. White pieces move in a clockwise direction, Black moves in an anti-clockwise direction. Since the inner tables point towards the light, it should therefore be clear who sits where.

For the purposes of describing the starting position, the points will be numbered1 to 12 on either side of the board starting with the first square of the inner table and finishing with the last square of the outer table. On Black's side, position 2 white pieces on point 1, 5 black pieces on square 6, 3 black pieces on square 8 and five white pieces on square 12. White's side should mirror this arrangement exactly.

Although Backgammon is played for stakes, this does not necessarily mean money - one can use counters, beans or one can just keep a score with pen and paper. However, the gambling element can be eliminated completely by following the normal rules and merely ignoring the doubling cube and the stakes. Normally, however, a stake is decided up front be it monetary or otherwise.

To begin, each player rolls one die each at the same time. If a double is rolled, then the stake is doubled and both players roll again. This is repeated until one player rolls a higher number than the other. The player with the highest throw then uses the dice throw from both players to take the first turn and also chooses to play white or black (and thus which side to sit).

Doubling and stakes

At any time after the first turn, either player can offer to double the stakes prior to casting the dice. Upon being presented with such an ultimatum, the other player must choose either to forfeit the game and the current stake or accept the offer.

Once the stake has been doubled once in this way, only the player who accepted the most recent offer to double the stake can offer to re-double it. Whenever this happens, the other player either forfeits the game or accepts the double and the opportunity to offer the next double.

The doubling cube is used to record the current amount of the stake.

Basic Play

Each turn consists of the opportunity to move counters towards the player's inner table according to the roll of the two dice. Unless a double is thrown, two moves are allowed, one for each number on the dice. When a double is thrown, four moves are allowed of the number on the dice. Player's are not allowed to pass on their moves - as many moves as possible must be made each turn.

• A point with two or more pieces of the same colour on it is safe - the opponent cannot land a piece on such a point..
• A point hosting only one piece is called a "blot". Such a piece is vulnerable - if the opponent lands on this point the piece is captured and moved to the bar (this means physically placed on the middle bar dividing the board).
• Captured pieces are re-entered on the furthest point from the player's inner table. A throw of 1 allows the piece to move from the bar to point one of the opponent's inner table. A throw of 5 allows the piece to enter at point 5 of the opponent's inner table.
• If a player has one or more pieces on the bar, no other pieces can be moved until all such pieces have re-entered play. So if the dice throw and position of enemy pieces prevents a player from re-entering a piece onto the board from the bar, the player cannot move any other piece and play passes to the opponent.

A point hosting two or more of the opponent's pieces is said to be "blocked". If six points in a row are blocked, the opponent is said to have formed a "prime". This is a highly advantageous achievement because a prime cannot be traversed by an opponent but is completely free to be traversed by the player who created it.

Bearing Off

Once all pieces are present in a player's inner table, that player can start "bearing off". A throw of 1 allows a player to bear off a piece from point 1 of his inner table, a throw of 2 allows a player to bear off a piece from point 2 of his inner table and so on. Pieces borne off are simply removed from the board. Player's do not have to bear off - if available, they can choose to move a piece within their inner table instead. This is often done to pair up singlets in order to prevent them from capture.

When a player rolls a number that is higher than the highest point of the inner table upon which that player has pieces, the player is allowed to bear off the next highest piece. For example, with a roll of double 5, if the player has a piece on point 5, two pieces on point 3, one piece on point 2 and one piece on point 1, the player would bear off the four highest placed pieces and be left with just one piece on point 1.

If after starting to bear off, a player's piece is captured, that piece must re-enter at the other side of the board and bearing off cannot re-start until all pieces are once again residing in the inner table.

Finishing

The first player to bear off all pieces wins the game.

• If the opponent has borne off at least one piece, a single game is won and the current stake is forfeited.
• If the opponent has not borne off any pieces, this is a "gammon" and worth double the current stake.
• If the opponent has a piece left on the bar or within the opponent's inner table, this is a "backgammon" and worth triple the current stake.

Strategy

Strategy for the classic Backgammon game, implemented using concepts of Artificial Intelligence

Game Holding Strategy Plan on keeping a point in your control that is located highly in your opponent’s board, usually a point in his inner board or the bar point.

The 20 point or bar points are the best holding game anchors, as they provide maximum chances to hit your opponent as he brings his checkers closer to home. Points further back get much weaker.

Another key strategic element to the holding game is the distribution of the opponent’s checkers. If he has only the 8 and 13 points made (as in the starting position), he will often have to leave a shot as he brings his checkers around. If he has made additional landing points in his outer board, your hitting chances go down significantly.