Backgammon

Backgammon is a two-player board game of strategy and chance, played on a board consisting of twenty-four narrow triangles called points, where players move their pieces according to the roll of dice with the objective of bearing off all their pieces before their opponent.

History and Origins

The origins of backgammon can be traced back nearly 5,000 years to archaeological discoveries in the Middle East, particularly in ancient Mesopotamia and Persia. The modern game is a direct descendant of the ancient Roman game Tabula, which itself evolved from earlier Egyptian and Sumerian board games. The game gained immense popularity in Europe during the Middle Ages. The term "backgammon" first appeared in print in the mid-17th century, likely derived from the Middle English words baec (back) and gamen (game). In 1743, Edmond Hoyle published A Short Treatise on the Game of Back-Gammon, which codified the rules and established the strategic principles that largely govern the game today. The most significant modern innovation was the introduction of the doubling cube in the 1920s in New York, which transformed backgammon from a mere gambling pastime into a profound game of probability and risk management.

Equipment

A standard backgammon set includes a board, thirty checkers (fifteen for each player, typically in two contrasting colors), two pairs of six-sided dice, two dice cups, and a doubling cube. The board consists of twenty-four narrow triangles called points, alternating in color and grouped into four quadrants of six points each. These quadrants are referred to as a player's home board (or inner board) and outer board, and the opponent's home board and outer board. The home and outer boards are separated by a central ridge down the middle of the board called the bar. The doubling cube is a larger die with the numbers 2, 4, 8, 16, 32, and 64 printed on its faces, used to track the current stake of the game.

Setup and Objective

At the beginning of the game, each player's fifteen checkers are arranged in a specific starting position: two checkers on their 24-point, five on their 13-point, three on their 8-point, and five on their 6-point. The points are numbered for each player starting in their home board, meaning the 24-point for one player is the 1-point for the other. The primary objective of the game is to move all of one's checkers into one's own home board and then "bear them off" (remove them from the board). The first player to bear off all fifteen checkers wins the game.

Rules of Play

Players take turns rolling two dice and moving their checkers according to the numbers shown. The dice must be rolled flat on the right-hand side of the board. A player can move one checker for the total of both dice, or two separate checkers for each die. If a player rolls doubles (e.g., two 4s), they play the numbers shown on the dice twice (four moves of 4).

Checkers always move forward, to a lower-numbered point in the player's home direction. A checker may only be moved to an open point—one that is not occupied by two or more opposing checkers. If a player lands on a point occupied by a single opposing checker (known as a "blot"), the blot is "hit" and placed on the bar. A player with one or more checkers on the bar must first re-enter them into the opponent's home board before making any other moves. Re-entry is only possible on points that are not blocked by two or more opponent checkers.

Once a player has moved all fifteen of their checkers into their home board, they may begin bearing off. A checker is borne off by rolling a number that corresponds to the point on which it resides. If no checker is on the point rolled, the player must make a legal move using a checker on a higher-numbered point.

The Doubling Cube

The doubling cube is a unique feature that adds a deep layer of strategy to backgammon. At the start of the game, the cube is placed in the middle with the 64 face up, indicating a stake of 1. During the game, a player who believes they have an advantage may propose to double the stakes before rolling the dice. The opponent must either accept the double (taking control of the cube and the right to redouble later) or decline it, thereby forfeiting the game and losing the current stake. The cube introduces complex mathematical and psychological elements, requiring players to accurately evaluate their winning probabilities and risk tolerance.

Strategy and Tactics

Backgammon strategy is broadly categorized into several game plans. The "running game" involves moving checkers as quickly as possible toward the home board, which is optimal when a player is ahead in the race. The "holding game" involves maintaining an anchor (two or more checkers) in the opponent's home board to block their progress and create opportunities to hit their blots. The "priming game" focuses on building a "prime"—a continuous wall of blocked points—to trap the opponent's checkers behind it. The "backgame" is a defensive strategy used when significantly behind, involving holding two or more anchors in the opponent's home board to hit a late shot.

Advanced players rely heavily on "pip counts" (the total number of pips required to bear off all checkers) to evaluate racing positions, and they use probability mathematics to assess the risks of leaving blots. Since the 1990s, the development of artificial neural network programs, most notably TD-Gammon, has revolutionized backgammon strategy, disproving many traditional heuristics and establishing new, mathematically optimal approaches to opening moves and mid-game decisions.

Variants and Related Games

Numerous regional variants and related games exist worldwide. Acey-deucey is a popular variant among the United States Navy, where rolling a 1-2 allows the player to choose any doubles to play. Nackgammon, invented by Nack Ballard, uses the same rules but a different starting position that encourages more complex backgames and priming battles. Hypergammon is played with only three checkers per player, resulting in a highly tactical and fast-paced game. Culturally related games include Tavla in Turkey, Shesh Besh in the Middle East, and Portes in Greece, which share the same board and basic movement mechanics but feature slight rule variations.

Competitive Play and Organizations

Backgammon is played competitively in clubs and tournaments around the world. The World Backgammon Championship, held annually in Monte Carlo since the 1970s, is considered the most prestigious event in the sport. The World Backgammon Federation (WBF) and various national organizations oversee tournament rules, rankings, and the promotion of the game. In recent decades, the rise of online backgammon servers and mobile applications has significantly expanded the global player base, allowing for continuous competitive play, matchmaking, and the use of real-time equity analysis tools for post-game study.