Backgammon

Rules and how to play

The board has 24 long, narrow triangles called points, and White and Black each have 15 checkers, also called men. In Backgammon, “checkers” means the playing pieces, not the game of Checkers. Players take turns rolling 2 dice and move checkers by the numbers rolled. You move your checkers from your 24-point toward your 1-point, as numbered from your side, bring all 15 into your home board (points 1–6), and then bear them off the board. The first player to bear off all 15 checkers wins.^[1]

Each player numbers the points from their own side. Your 24-point is your opponent’s 1-point, and White and Black move in opposite directions. In the starting position, each player has, counting from their own side, 2 checkers on the 24-point, 5 on the 13-point, 3 on the 8-point, and 5 on the 6-point.^[1]

To start, each player rolls 1 die, and the player with the higher number moves first, using those 2 numbers (if the numbers are the same, both players roll again). After that, players take turns rolling 2 dice and moving.^[9]

The 2 numbers are used separately, and each one moves a checker that many points. You can move 1 checker with both numbers in a row or split them between 2 checkers (when you move 1 checker with both, it must also be able to stop on the point in between). When you roll doubles, you use the same number 4 times. You cannot land on a point that has 2 or more of your opponent’s checkers, but you can jump over it.^[1][9]

You use as many of the rolled numbers as possible. If only one of the numbers can be used, you use the larger one if it can be played. If neither number can be used, you do not move, and it becomes your opponent’s turn.^[9]

When you land on a point that has only 1 of your opponent’s checkers (a blot), you hit that checker and place it on the bar in the middle of the board. A player with a checker on the bar must bring it back into the opponent’s home board (points 19–24 from their own side) before moving any other checker. A 1 enters on the 24-point and a 6 on the 19-point, and a checker cannot enter a point that has 2 or more of the opponent’s checkers. If no number lets the checker enter, that player cannot move that turn (this is called dancing).^[1][9]

Once all 15 of your checkers are in your home board, you can bear off a checker from the point that matches the number rolled. If there is no checker on that point or on any higher-numbered point, you can bear off a checker from the highest-numbered point that has one. You may also move checkers within your home board instead of bearing off. If one of your checkers is hit while you are bearing off, you cannot bear off again until that checker returns to your home board.^[1][2]

When you win, it is a gammon (a win worth 2 points) if your opponent has not borne off any checkers, and a backgammon (a win worth 3 points) if, in addition, your opponent still has a checker on the bar or in your home board.^[1][9]

This page does not use the doubling cube, which doubles the stakes. A game that ends in a resignation counts as a single game (1 point), and the result of each game is shown as a single game, a gammon, or a backgammon.

Controls on this page

Choose how to play in the panel to the right of the board (below it on narrow screens). Press “Easy”, “Medium”, or “Hard” under “Play vs computer” to start a game, and you play White. To play Black, press “Play Black · Medium”. The opening roll decides who moves first. With “2 players on this device”, you take turns using a single device.

When it is your turn, press the dice on the board or “Roll the dice”. Checkers you can move get a gold ring. Press a checker, and its destination points turn gold with a translucent checker on them. Press a destination to move there. If only one place has checkers you can move (for example, when entering from the bar), the destinations appear without you having to press a checker. To bear off, press the tray at the right end of the board.

Use the rolled numbers one at a time to move checkers. When you are done, press “Confirm”, and it becomes your opponent’s turn. Until you confirm, “Undo step” cancels your last step. When playing the computer or with 2 players on this device, “Undo move” takes you back to just before the last move you made, even after you confirm. Undoing does not change the numbers you rolled. “Undo move” is not available between rolling the dice and confirming, or when playing a friend.

The “Button controls” panel to the right of the board (below it on narrow screens) offers the same controls. The moves you can make next are listed as buttons such as “13 → 8 (5)”, and the panel also shows both players’ pip counts, the moves so far, and the checker positions as text. Use it when playing with a keyboard or a screen reader. The numbers on the edge of the board and on the buttons are counted from the side of the player sitting at the near side (with 2 players on this device, they switch to the side of the player whose turn it is).

Drag the board to rotate the view. Use the mouse wheel or pinch to zoom in and out, and switch views with the “Angled” and “Top-down” buttons at the top right of the board.

To play a friend, press “Play a friend (send a link)” and send the link shown to your opponent. The game starts when they open the link and press “Join”. The host plays White, and the player who joins plays Black. If your opponent stays disconnected for 2 minutes, you can continue against the computer. After the game, press “Rematch (swap White and Black)” to start the next game with White and Black swapped.

Strategy tips

• If your opening roll is 3 and 1, the standard play is to move 1 checker each from the 8-point and the 6-point to make the 5-point. With 4 and 2, make the 4-point from the 8 and 6. With 5 and 3, make the 3-point from the 8 and 6. With 6 and 1, make the 7-point from the 13 and 8.
• A checker alone on a point (a blot) goes to the bar when it is hit, and it has to start again from your opponent’s home board. A blot 1–6 points in front of an opposing checker is hit by 11–17 of the 36 possible rolls. At 7–12 points away, it is hit by 2–6 rolls (when the points in between are not blocked).
• Making several points in a row, each with 2 or more of your checkers, makes it hard for your opponent’s checkers to get past. With 6 in a row (a prime), your opponent cannot get past with any roll.
• Filling the points in your home board with 2 or more checkers each makes it hard for an opposing checker you have hit to enter from the bar. If you fill all 6, your opponent cannot enter from the bar and cannot move that turn.
• Once the checkers have passed each other and neither side can hit (a race), the side with the lower pip count (the total number of points its checkers still have to move to bear off) has the advantage. Both sides start with a pip count of 167. This page shows both pip counts in the “Button controls” panel.

Origin and history of Backgammon

Games in which each player moves 15 checkers on a board of 24 points by the roll of dice, and the first to bear them all off wins, have existed in many places since ancient times. A poem describing a game played by Zeno, the Eastern Roman emperor, in the 5th century mentions “tabula”. The board, the number of checkers, and the rule that the first player to bear off all checkers wins were the same in tabula as in Backgammon, but tabula used 3 dice. In Persia and elsewhere in western Asia, a related game called “nard” developed.^[7][9]

Games of the same family also reached Japan by way of China, and in Japan they were called ban-sugoroku (盤双六, board sugoroku). Players set out 15 white and 15 black pieces and move them by the roll of 2 dice. The chronicle “日本書紀” (Nihon Shoki) [Chronicles of Japan] records a ban on sugoroku in 689, and the Shosoin repository still holds a rosewood sugoroku board with wood marquetry (木画紫檀双六局) from the Nara period (710–794). Ban-sugoroku fell out of use in the late Edo period (1603–1868), and paper picture sugoroku (e-sugoroku), which grew out of ban-sugoroku, spread in its place.^[3][4]

The English name “backgammon” appears in records from the 1640s. Before that, games of this family were called “tables” in England. The name combines “back” with “gamen”, the Middle English word for “game”, and is thought to refer to checkers sometimes being sent back. In the 1740s, the English writer Edmond Hoyle published a guide to Backgammon that counted the 36 ways 2 dice can fall and showed the probability of a checker being hit.^[5][8]

In the 1920s, after World War I, the doubling cube, which lets players double the stakes during a game, was invented in New York in the United States. From 1920 to 1926, the game’s popularity spread from New York across the United States, and “Modern Backgammon”, a guide published in 1927, is considered the first book to explain the doubling cube.^[6][7][9]

Sources

1. Japan Backgammon League, “バックギャモンのルール（基本編）” [Backgammon rules (basics)] (in Japanese) (opens in a new tab)
2. Backgammon Galore, “Rules of Backgammon” (bkgm.com) (opens in a new tab)
3. Imperial Household Agency, “木画紫檀双六局” [Rosewood sugoroku board with wood marquetry] (Shosoin Treasures database; in Japanese) (opens in a new tab)
4. Kotobank, “双六” [Sugoroku] (entries from Nihon Daihyakka Zensho (Nipponica), Yamakawa Nihonshi Shojiten (revised edition), and others; in Japanese) (opens in a new tab)
5. Edmond Hoyle, “A Short Treatise on the Game of Back-Gammon” (transcription of the 1744 edition, bkgm.com) (opens in a new tab)
6. The Gammon Press, “A Short History of Modern Backgammon” (2016) (opens in a new tab)
7. James Masters, “Backgammon - History and Useful Information” (The Online Guide to Traditional Games) (opens in a new tab)
8. Online Etymology Dictionary, “backgammon” (opens in a new tab)
9. Wikipedia (English), “Backgammon” (opens in a new tab)

Frequently asked questions

What is the starting position in Backgammon?

Each player, counting from their own side, places 2 checkers on the 24-point, 5 on the 13-point, 3 on the 8-point, and 5 on the 6-point (15 in total). The 1-point is the point in your home board closest to where your checkers are borne off, and you and your opponent count in opposite directions. On this page, the checkers are placed in this position from the start.

What happens when you roll doubles?

You use the same number 4 times. For example, with double 4s, you make 4 moves of 4 points each. You can move a single checker for all of them or split them among different checkers. For the opening roll, each player rolls 1 die and both roll again on a tie, so the first turn is never doubles.

What are a gammon and a backgammon?

They’re names for how much a win is worth. If you win before your opponent has borne off any checkers, it’s a gammon, worth 2 points. If, in addition, your opponent still has a checker on the bar or in your home board, it’s a backgammon, worth 3 points. Any other win is a single game, worth 1 point. On this page, the result shows which kind of win it was.

Can I use the doubling cube?

No. On this page, each game is simply won or lost on its own, and there’s no way to double the stakes during a game. There’s also no feature for adding up points across games. Results are shown as a single game (1 point), gammon (2 points), or backgammon (3 points).

What if you can’t move with your roll, or can use only one of the numbers?

If you can’t move with either number, you don’t move, and it becomes your opponent’s turn. When that happens, the message on the board and the “Moves so far” log show that you couldn’t move. If you can use only one of the numbers, you use the larger one if it can be played. If there’s a way to move that uses both numbers, you can only choose a way that uses both.

How are the dice rolls decided? Are they rigged in the computer’s favor?

When playing the computer or with 2 players on this device, rolls come from your browser’s cryptographic random number generator (crypto.getRandomValues). When playing a friend, they come from the game server’s random number generator. Each roll is drawn without bias from the 36 possible outcomes. Because the dice are drawn at the moment you roll, the computer doesn’t know what the next roll will be. The computer on Hard chooses its moves by weighting the 21 different rolls its opponent could get by how likely each one is.

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