How to Play Backgammon: Rules, Odds, Tactics and History

1The board and the setup

The board has 24 narrow triangles called points, in four quarters of six, with a ridge down the middle called the bar. Points are numbered from your side: your home board is points 1 to 6, your outer board 7 to 12, then your opponent's outer board (13 to 18) and their home board (19 to 24). Your opponent numbers them the other way round, so your 24 point is their 1 point.

You move your checkers from 24 down to 1: along the top from right to left, down, along the bottom from left to right, and finally off the board. Your opponent goes the opposite way, so the two armies pass each other.

Add up how far every checker still has to go and you get your pip count: 167 each at the start. It is the simplest way to see who is ahead in the race.

2Moving: two dice, and doubles

Roll two dice. Each number is a separate move: you can move two checkers, one by each number, or one checker by both, one number after the other.

A checker can land on any point that is empty, holds your own checkers, or holds just one enemy checker. It can never land on a point with two or more enemy checkers. When you move one checker by both numbers, the point it stops on in between has to be open too.

Two more rules decide what you have to play:

• Use both numbers if you can. If there is any way to play both, you must play both (all four, with doubles).
• If only one can be played, play the bigger one when that's possible. If neither can be played, your turn is over.

Our board never asks you to work this out: it only lets you pick moves that keep to these rules. If you can't move at all, it passes your turn for you; otherwise you tap Done once your dice are played.

On average a roll moves you 8.17 pips, counting doubles four times. A double 6 is worth 24.

3Hitting, and the odds of being hit

A checker on its own is a blot. If your opponent lands on it, it is hit: it goes onto the bar, and it has to come back in at the far end and start its whole journey again. A blot deep in your home board loses almost all its progress. Two or more checkers on a point are safe.

How likely a hit is depends on the distance. Within 6 pips, a single die can do it, so the chance is high: 31% to 47%. From 7 pips on it takes both dice, and the chance falls to 17% or less:

Rolls out of 36 that hit a blot this many pips in front of one enemy checker, with nothing in between to block the way. Exactly 6 pips away is the worst place to stop.

Beyond 12 pips only doubles reach, and only some distances: a blot 15, 16, 18 or 20 pips away is hit by just 1 roll in 36, and at 13 or 14 pips one checker can't hit it at all. Every point your opponent can't land on between the hitter and your blot blocks some of these rolls, which is one more reason to make points.

4The bar: coming back in

A checker on the bar re-enters in your opponent's home board: a roll of 1 puts it on your 24 point, a 2 on your 23 point, and so on to a 6 on your 19 point. It can enter only on a point that is open to you.

• While you have a checker on the bar, you can't move anything else. Bring it in first.
• If neither number lets it in, you can't move at all this turn.

Every point your opponent closes in their home board makes it harder to get back in:

It works both ways. Each point you make in your home board shuts a door on your opponent's hit checkers. Close all six and a checker on the bar can't come in at all until you open one.

5Bearing off

Once all 15 of your checkers are in your home board, you can start taking them off. A roll of 6 bears off a checker from the 6 point, a 5 from the 5 point, and so on. You can also use a number to move a checker inside your home board instead.

• If you roll a number higher than your highest point, you bear off from your highest point.
• If one of your checkers is hit while you're bearing off, it has to come all the way round and home again before you bear off any more.

Near the end it's all about the dice. Two checkers left on your 1 and 2 points come off with any roll (100%). Two on your 6 and 5 points need a 6-5 or a big double: 6 rolls in 36 (17%). Two on the 6 point need a double 3 or higher: 11%.

6Winning: gammons and backgammons

The first player to bear off all 15 checkers wins. How big the win is depends on the loser:

In our game a gammon or a backgammon earns you extra XP on top of the win. They are not rare: when we played our computer opponent at its strongest against itself, 18% of games ended in a gammon and another 7% in a backgammon.

7Four habits, tested

Backgammon strategy fills books. These are the beginner habits that made the biggest difference when we put them to the test. We took our own computer opponent at its strongest and played 4,000 games against a copy of itself with one habit changed, swapping seats and who rolls first every game.

1. Hit when you can. Sending a checker back costs your opponent every pip it had travelled, plus a turn spent getting back in.
2. Count the shots before you leave a blot. Use the chart above: 6 pips in front of an enemy checker is 47%; 11 pips is 6%.
3. Worry about shots, not blots. A blot nothing can reach is fine. Breaking up your position to leave fewer blots is not.
4. Don't play scared. The play that leaves no shot at all is not always the best one.

The last one is "count the shots" turned into a blunt rule, and it loses: safety matters, but not at any price. Hitting matters enormously too. Weigh the two against each other on each roll.

What about making points, building a wall, not stacking? They matter: the entry table above shows what a closed home board does. But as separate habits, on top of hitting and counting shots, each one added little in our games (53% for valuing home-board points, 51% for walls of points in a row, 52% for not piling checkers up). A made point is two checkers, so a player who counts shots is already making them.

Does going first matter? Against our computer opponent you always roll first, and it makes no real difference: across 12,000 games between two copies of our strongest opponent, whoever rolled first won 50%.

8TriGammon: backgammon for three

TriGammon is our three-player version, on a Y-shaped board: 3 arms of 12 points each, 36 points in all, and 15 checkers for each of the 3 players.

• Your track is still 24 points. Your checkers come in along the arm you start on, round the centre, and out along your own home arm to its tip. They start on your own 24, 13, 8 and 6 points, just like backgammon (167 pips).
• Every arm is shared by two players moving opposite ways. Your home arm is where the next player starts, so you hunt one opponent. The arm you start on is the previous player's home arm, so the other one hunts you. The third arm is never on your track.
• Moving, hitting, the bar and bearing off are backgammon's rules, played on your own 24 points. In fact, our game runs the same rules engine as our Backgammon, on each player's view of the Y. A hit checker comes back in on the six points at the tip of the arm it started on.
• The first roll: each player rolls one die. The highest starts and plays the two highest numbers showing; if two players tie for highest, only they roll again.
• The end: the first to bear off all 15 wins and the game stops. Second and third go to whoever has fewer pips left. No gammons.

TriGammon comes from a page on William A. Sethares's website, where each player meets one opponent in the first half of the journey and the other in the second.[1] That page leaves the opening roll and the order of finish open, so those two are our own rules.

9Our rules, and other versions

Our Backgammon plays the standard moves: the setup, the dice, hitting, the bar and bearing off above are the rules you'll find on any board. Where we differ is in what sits around the game:

• No doubling cube. Every game is played to the end for a single win, a gammon or a backgammon.
• One game at a time, not a match to a set number of points.
• You roll first against the computer, and the player who opened an online table rolls first there. Your first roll is an ordinary roll of two dice, so it can be a double.
• Gammons and backgammons earn extra XP instead of counting double or triple.

The rules you'll meet elsewhere:

• The opening roll. In the standard game each player throws one die, and a tie throws again. The higher number moves first, playing both dice as thrown, so the first move is never a double.[2][3]
• The doubling cube. At the start of your turn, before you roll, you can offer to double the stakes. Your opponent either plays on for twice as much, and takes the cube (only they can double next), or gives up the game.[2] A game is then worth the cube's value, a gammon twice that and a backgammon three times.[2][4]
• Matches. Tournaments play matches to a set number of points. Under the Crawford rule, the game after either player gets within one point of winning is played without the cube.[5]
• Money play has two optional extras: the Jacoby rule (gammons count only once someone has doubled) and the beaver (a player who has just been doubled can double straight back and keep the cube). Neither is allowed in tournaments.[2][6]

And other games on the same board:

• Nackgammon, from Nack Ballard: each side starts with four checkers at the back instead of two.[7]
• Hyper-backgammon: three checkers each, a game simple enough for computers to analyse completely.[8]
• Acey-deucey, long played in the US Navy: every checker starts off the board, and a roll of 1-2 lets you pick any double you like.[9]
• Tavli, in Greece, is three games played in turn: portes, close to backgammon; plakoto, where you pin a lone enemy checker instead of hitting it; and fevga, where there is no hitting, a single checker holds its point, and both players move the same way round.[10]
• Long nardy, played as an official sport in Russia, has no hitting either: you can't land on a point where an enemy checker stands.[3]

10A short history

An old family, a younger game. Backgammon belongs to one of the oldest families of board games. The game with that name, and with the doubling cube, took shape much later, between the 1600s and the 1920s.

The Romans played a dice race on a board of three rows of twelve, divided into sixes. It was called the game of twelve lines, duodecim scripta, and later simply alea, "dice".[11] According to the classicist R. G. Austin, a quicker game grew out of it when the middle row was dropped, leaving two rows of twelve.[12] The oldest game we can be sure had backgammon's numbers is in a Greek poem by Agathias, written in the 6th century AD. It describes a position from a game of tabla played by the Emperor Zeno, who reigned from 474 to 491: count the points and pieces and you get 24 points and 15 pieces a side, just as in backgammon. But Zeno threw three dice, not two.[13][12]

In Persia the game is nard. Persian tradition puts its invention in the 3rd or the 6th century AD, and the oldest object that shows it is a 7th-century bowl of gilded silver.[11] A Middle Persian text, the Wizārišn ī čatrang, tells how the sage Wuzurgmihr invented it: the board stands for the earth, the 30 pieces for the days and nights of a month, and the throw for the turning of the stars.[11][14] Scholars date the core of the text to the late Sasanian period, but treat the story itself as legend.[14]

Not 5,000 years old. A board from the Burnt City (Shahr-e Sukhteh) in Iran is often called the world's oldest backgammon set. It isn't backgammon: it is a 20-square race board, from the same family as the Royal Game of Ur, and backgammon's board doesn't come from that family.[11]

Medieval Europe played many games on the backgammon board. In 1283 Alfonso X of Castile's Book of Chess, Dice and Tables described a whole family of them, one of which, todas tablas, was set up like modern backgammon.[15][16] The English word backgammon is first recorded in the mid-1600s. Where it comes from is uncertain, though "gammon" may be an old form of "game".[17][18] In 1743 Edmond Hoyle published A Short Treatise on the Game of Back-Gammon, with "The Laws of the Game".[19]

Doubling, the idea behind the cube, reached New York's clubs in the late 1920s, and the doubling cube itself appears by 1930.[20][21] In 1931 a committee at New York's Racquet and Tennis Club, organised by Wheaton Vaughan, drew up Laws of Backgammon that included doubling.[20] The game boomed again in the 1960s. In 1964 Prince Alexis Obolensky held the first international tournament, in the Bahamas,[22][23] and in 1967 Las Vegas hosted the first event called a World Championship, won by Tim Holland.[22][24]

Backgammon also made computer history. In the early 1990s Gerald Tesauro, at IBM, built TD-Gammon, a program that taught itself the game by playing against itself, and it came close to the level of the best human players.[25]

Sources

1. William A. Sethares, "TriGammon – Backgammon for Three Players", University of Wisconsin–Madison. sethares.engr.wisc.edu
2. U.S. Backgammon Federation (USBGF Education Team), "Backgammon Basics: How to Play", rules text from Tom Keith's Backgammon Galore. usbgf.org
3. Ministry of Sport of the Russian Federation, Rules of the sport "nardy" (Правила вида спорта «нарды»), order no. 347, 30 April 2025, §§ 20, 26. pravo.ppt.ru
4. Encyclopaedia Britannica, "backgammon". britannica.com
5. U.S. Backgammon Federation, Tournament Rules, 2025. usbgf.org (PDF)
6. World Backgammon Federation, Tournament Rules, edition 2.1, 2023, § 4.4. wbgf.info (PDF)
7. Kit Woolsey, "Nackgammon", GammOnLine, September 2001, reprinted at bkgm.com. bkgm.com
8. GNU Backgammon manual. gnu.org
9. Encyclopaedia Britannica, "acey-deucey". britannica.com
10. Tom Keith, Backgammon Galore: "Portes", "Plakoto" and "Fevga". bkgm.com
11. Ulrich Schädler and Anne-Elizabeth Dunn-Vaturi, "Board Games in pre-Islamic Persia", Encyclopaedia Iranica, 2009. iranicaonline.org
12. R. G. Austin, "Greek Board Games", Antiquity 14, 1940, pp. 257–271. web.archive.org
13. Agathias, in W. R. Paton (trans.), The Greek Anthology, vol. III, Loeb Classical Library, 1915, Book IX, no. 482, pp. 268–269. archive.org
14. Antonio Panaino, "Wizārišn ī čatrang ud nihišn ī nēw-ardaxšīr", Encyclopaedia Iranica, 2017. iranicaonline.org
15. Universidad Complutense de Madrid, Biblioteca, Alfonso X, Libro del ajedrez, dados y tablas, 1283 (El Escorial, RBME Ms. T-I-6). biblioteca.ucm.es
16. Ludii Portal (Digital Ludeme Project), "Todas Tablas", after the Libro de los juegos and H. J. R. Murray (1951). ludii.games
17. Dictionary.com (Random House), "backgammon" and "gammon". dictionary.com
18. Collins English Dictionary, "backgammon". thefreedictionary.com
19. Edmond Hoyle, A Short Treatise on the Game of Back-Gammon, London, 1743. archive.org
20. Albert Steg, "A 1930's Chronology", BG Museum, New England Backgammon Club. nebackgammon.org
21. Oswald Jacoby, "Backgammon History", Las Vegas Backgammon Magazine, December 1981, reprinted at bkgm.com. bkgm.com
22. U.S. Backgammon Federation, American Backgammon Hall of Fame, "Alexis Obolensky". usbgf.org
23. Edwin Shrake, "Everyone for Backgammon", Sports Illustrated, 3 May 1964, reprinted at bkgm.com. bkgm.com
24. U.S. Backgammon Federation, American Backgammon Hall of Fame, "Tim Holland". usbgf.org
25. Gerald Tesauro, "Temporal Difference Learning and TD-Gammon", Communications of the ACM 38(3), 1995. bkgm.com

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