Backgammon is a board game for two players. Each player has fifteen pieces (checkers) which move between twenty-four triangles (points) according to the roll of two dice. The objective of the game is to be first to bear off, that is, to move all fifteen checkers off the board. The oldest recorded game in history, backgammon traces its roots to the ancient Mesopotamian game tabula, which appears in an epigram of Byzantine Emperor Zeno (476–481 A.D.). Further archaeological excavations have placed the possible date of origin of backgammon to 3000 B.C.
Though the gameplay is quite basic—each player is trying to move his checkers to his home board and then bear them off before his opponent is able to do so—backgammon incorporates strategy insofar as with each dice roll, the player must choose between multiple options for movement of the checkers. Furthermore, the doubling cube, which raises the stakes of the present game when a match consists of multiple games, and rules like the Crawford Rule and the Jacoby Rule, introduce more strategic intricacies. Experts have also developed a nomenclature to define commonly used general strategies for play such as the running game and the backgame.
As with chess, backgammon has been significantly interfaced with computer technology. By 1979, Hans Berliner’s BKG 9.8 program had defeated a world champion backgammon player, and since then neural network and other approaches have improved the playing quality of the virtual backgammon opponent. In addition, a number of other computer programs, most notably the backgammon software Snowie, have combined the capabilities of an intelligent opponent with extensive statistical analyses of individual moves and possible outcomes.
Medieval tabula players, from the 13th century Carmina Burana
Backgammon is the oldest known recorded game. Traditionally, it was believed to have originated in ancient Mesopotamia, (present-day Iraq), also see Royal Game of Ur. In English, the word backgammon is believed to be derived from “back” plus the Middle English word “gamen” (game).
Medieval backgammon players
Tabula was a form of backgammon played by the ancient Romans. It was called tabula, which means ‘table’ or ‘board’, since it was played on a special board. Tabula bears some similarity to Egyptian Senet, which dates back to at least 3000 BC.
The game of Tabula was similar to modern-day Backgammon in that the same board was used with fifteen pieces alloted to each player with the object of the game being to be the first to bear off all fifteen pieces. It differed in that the game began with no pieces on the board so that these first had to be entered by the roll of the dice. Likewise, three dice were used instead of two. Finally, both players entered the board from the same table and moved around the board in the same counterclockwise direction.
Recent excavations at the “Burnt City” in Iran showed that a form of backgammon existed there around 3000 BC. The artifacts include two dice and 60 pieces. The set is believed to be 100 to 200 years older than the oldest set found in Ur.
Backgammon set, 19th century
Backgammon as a gambling game
Backgammon is often played for money stakes. The most common ways that gamblers play is to set a wager on which player can be first to reach a certain score, achieved over however many games necessary; to assign a monetary value to each game (affected by the doubling die, of course), and to play until a certain score is reached or passed; or to assign a monetary value to each game and play games until either player chooses to stop. Backgammon is also available, though not often, at casinos.
A backgammon chouette is an adaptation of backgammon for three or more players, generally played for money.
Before beginning, a monetary value is agreed upon as the basic stake for each game. Dice throws determine an initial ranking. One player is in the box, the next is the captain, and the others take their places as members of the captain’s team. The captain, who may take advice from the team, plays against the player in the box. Traditionally, there is one doubling cube. This is controlled by the player in the box and the captain (in the usual way), except that, when the player in the box offers a double, each member of the team may accept or decline independently. Nowadays, however, the team members often operate separate doubling cubes, in which case they may accept, decline and offer doubles independently. Whichever system is employed, a team member who has refused a double drops out of the game and may no longer advise the captain. If the captain drops out of the game, the highest-ranking team member takes over as captain.
At the end of each game, the box settles up with the other players individually. If the player in the box has won, he retains the box and the (original) captain becomes the lowest-ranking team member. If the (final) captain has won, he takes over from the player in the box, who joins the team as its lowest-ranking member. The highest-ranking member of the team becomes its captain for the next game.[The word ‘chouette’ is French for any of a seemingly arbitrary collection of species of typical (i.e. non-barn) owls.]
Backgammon in the Middle East and Central Asia
Backgammon is widely played in the Middle East and Central Asia, particularly in cafes. There are four main variants played in the Middle East:
1) the European game as described above and known as ifranjiah (meaning Frankish in Arabic); “Takhte Nard” is the Iranian version.
2) shesh besh (Shesh means six in Persian and Hebrew and Besh means five in Turkish) in Azerbaijan, Israel, and Uzbekistan and tavla in Turkey;
3) mahbusa (meaning ‘imprisoned’)
The most popular of those is probably mahbusa. In this game each player’s 15 checkers are all initially positioned on his 24-point. When hit, an isolated checker is not placed on the bar. Rather the hitting piece sits on top of the hit piece forming a block, i.e. the same rules apply as if the point was occupied by two or more pieces of the same colour. The checker which has been hit is ‘imprisoned’ and cannot be moved until the opponent removes his piece: hence the name of the game. Sometimes a further rule requires that a player must bring his first checker to the opponent’s home board before moving any other checkers. Whether or not this rule is applied, a rapid advance to the opponent’s side of the board is desirable as imprisoning the opponent’s checkers on his home table is highly advantageous.
An interesting feature of backgammon as played in some Arab countries is that Persian or Kurdish numbers, rather than Arabic ones, are called out by a player announcing his dice rolls.
People in Iranian plateau and Caucasus region, especially in Iran, Armenia, Azerbaijan, and Georgia, are very fond of playing Narde. In Georgia they play mainly the “short Narde”, a slightly simplified version of ifranjiah. In Iran it is called “Takhte Nard”. In Armenia and Azerbaidjan experienced players prefer to play “long Narde”, which requires more skill and even “knowledge” of some non-written strategic methods. As in ‘mahbusa’ all 15 checkers of a player are initially positioned on his 24-point, but there is a principal difference. One is forbidden to put his checker at a point occupied by opponent’s checker. So there is no “hitting” and no “imprisonment” in the long Narde game. The main strategy is to secure playing “big pairs” by one’s own checkers and prevent as much as possible doing the same by the opponent.
A Swedish variant of backgammon, also called Swedish Tables in English.
The main difference compared to other backgammon variants is the method of winning. You can win by bearing off, but there are also several other ways to win, such as to arrange all your checkers in certain pre-determined patterns or by hitting so many checkers that your opponent can not bring them in again.
Brädspel is played without the doubling cube.
Gul bara is also called ‘Rosespring Backgammon’ or ‘Crazy Narde’ and mistakenly called ‘Gul Bahar’ in some Arab countries.
Old English Rule
This rule limits the number of checkers to a maximum of five on each point, thus restricting some moves that might otherwise be made. This variation of backgammon is popular in England (as well as other regions), and is viewed as making the gameplay more interesting.
The Runte Rule allows the player to move his checkers both backwards and forwards within his own home board. The player cannot move the checker in such a way that it lands outside of his home board. The rule was created to increase the possibility of scoring backgammons and gammons, because it allows one to trap the opponent for longer.
In Greece, backgammon is called tavli (related to the word tavla ‘board, table’, and cognate to the Latin Tabula). It consists of three main styles, Portes, Plakoto and Fevga. Portes resembles the standard game, with minor variations: There is no doubling cube and backgammon counts as a gammon (called diplo – greek word for a double). Plakoto is very similar to mahbusa or Tapa, while Fevga is similar to Narde or the Turkish variant Moultezim. The three are normally played consecutively, one after another, in matches of three, five or seven points.
In Republic of Macedonia the game is called tabla (табла, meaning ‘board, table’). It also consists of three main styles, very similar to the Greek tavli: Tabla, Gjul Bara and Tapa. They are played consecutively (in that order) in a match of five. The first game Tabla (Табла) is the standard backgammon, with few differences: there are no doubling cubes and there is no backgammon (it’s the same as gammon). Gjul Bara (Ѓул Бара) and Tapa (Тапа) are played the same way as described before. Gammon is called mars (марс) and it’s the only situation when a player can win 2 points with a single game. Mars is present in all three styles. When starting the match, each player rolls one die, to determine who will start. If it’s a tie, the players roll again. But, unlike the regular backgammon, the already-rolled dice are disregarded and the player that won the first turn, rolls both dice to begin. In the next game in the match, the player that won the previous has the first turn.
LongGammon is a variant of backgammon, the sole difference being that all fifteen of the players’ checkers start on their opponent’s one-point. All other rules of the game are the same as regular backgammon.
A variation invented by Nack Ballard. It differs from the regular game in its initial setup: each player starts with two checkers on their 24-point, two checkers on their 23-point, three checkers on their 8-point, and five checkers on their 13-point and on their 6-point. This setup places more emphasis on positional play.
Nackgammon is played using the doubling cube and the Jacoby rule, so gammons and backgammons count only if the cube has been turned.
The first strong computer opponent was BKG 9.8. It was programmed by Hans Berliner in the late 1970s on a PDP-10 as an experiment in evaluating board positions. Early versions of BKG played badly even against poor players, but Berliner noticed that the critical mistakes the program made were always at phase changes. He applied basic principles of fuzzy logic to smooth out the transition between phase changes, and by July 1979, BKG 9.8 was ready to play against then current world champion Luigi Villa. It won the match, 7-1, becoming the first computer program to defeat a world champion in any game, although this was mostly a matter of luck, as the computer happened to get better dice rolls than its opponent in that match.
Beginning in the late 1980s, creators of backgammon-playing software began to have even more success with a neural network approach. TD-Gammon, developed by Gerald Tesauro of IBM, was the first of these computer programs to play at or near the expert level. This program’s neural network was trained using Temporal Difference learning applied to data generated from self-play.
This line of research has resulted in two modern commercial programs, Jellyfish and Snowie, the shareware BGBlitz (implemented in Java), and the free software GNU Backgammon, that play on a par with the best human players in the world. It is worth noting that without their associated “weights” tables which represent hours or even months of tedious neural net training, these programs play no better than a human child.
It is interesting to compare the development of backgammon software with that of chess software:
- For backgammon, neural networks work better than any other methods so far. For chess, brute force searching, with sophisticated pruning and other refinements, works better than neural networks.
- Every advance in the power of computer hardware has significantly improved the strength of chess programs. In contrast, additional computing power appears to improve the strength of backgammon software only marginally.
- For both backgammon and chess, it is at present unclear whether the best computer or the best human is best overall. For most other games, one or the other is unambiguously stronger.
Real-time on-line play began with the First Internet Backgammon Server on July 19, 1992. This server is active to this day, remains free, and enjoys a strong international community of backgammon players. Several commercial websites also offer on-line real-time backgammon play
- The technology behind backgammon
- ODP Backgammon
- Backgammon Chouette Play Broad explanation of the chouette play.
- Gammon Links link collection.
- GnuBg open source neural net based backgammon program.