Backgammon

Backgammon is one of the oldest known board games — versions of it have been played for over 5,000 years. Two players each have 15 checkers on a 24-point board. Roll two dice, move checkers, try to bring all 15 of yours into your “home” quarter and then off the board. Combines luck (dice) with deep strategy (move choice). The game has been continuously played from ancient Mesopotamia through Persian and Greek civilizations to today’s online tournaments.

How to play

• You play white. Your checkers move counterclockwise: from point 24 (upper right) toward point 1 (lower right). Your home board is points 1-6.
• The computer plays black, moving clockwise: from point 1 toward point 24. CPU home is points 19-24.
• Click Roll dice each turn. You get two dice values (or four if you roll doubles).
• Click a checker, then click a legal destination point.
• Destination must be: empty, your own colour, or holding exactly one opponent checker (a “blot” you can hit).
• Hitting a blot sends that opponent checker to the bar. They must re-enter from your home board before moving anything else.
• Once all 15 of your checkers are in your home board (points 1-6 for white), you can bear off.
• First to bear off all 15 wins.

Beginner strategy

• Make points, especially in your home board. A “point” is two or more checkers on the same space. Opponents can’t land there.
• Avoid leaving blots. A single checker on a point can be hit, sending it back to start.
• Don’t ignore back checkers. If you race forward without securing your back two checkers, the opponent will build a wall that traps them.
• Pip count matters. Sum the distances all your checkers need to travel. If you’re 20+ pips behind, switch strategies.
• Doubles are huge. Rolling 4-4 lets you move four 4s. Plan as if doubles are possible.

Intermediate strategy

• The “prime” formation. 4-6 consecutive points in your home board create a wall that opponent’s back checkers can’t cross.
• The “anchor” defense. Two checkers on opponent’s 1-point (your 24-point) is the deep anchor — defensive position when behind.
• Race vs hold strategies. If you’re ahead in pip count, race. If behind, hold and wait for hits.
• Back-game strategy. When 20+ pips behind, hold deep anchors and wait for blots to hit.
• Bearing off precision. When bearing off, use exact dice rolls when possible to avoid wasted points.

Advanced strategy

• The doubling cube. Not implemented here, but the cube is a key strategic element in competitive backgammon. Players can double the stakes; opponent must accept or resign.
• Equity calculation. Top players calculate expected match equity in real-time.
• Bot-level play. Programs like GNU Backgammon and XG play significantly above human world champion level.
• Match play vs money game. Strategy differs based on whether you’re in a tournament match or single-game format.
• Opening rolls. Specific dice rolls (3-1, 4-2, 6-1) have standard optimal opening responses memorized by top players.

Backgammon math

• Dice probability. With 2 dice, certain combinations are more likely: 1+1, 6+6 each have 1/36 probability; 1+2 has 2/36 (because either die can be the 1).
• Pip count. Sum of distances. Lower = better.
• Equity. Expected probability of winning from a given position.
• Doubling cube math. Accept a doubled cube only if your win probability is 25%+ (rule of thumb).

Backgammon history

• ~3000 BC — Royal Game of Ur: Mesopotamian ancestor. Found in Iraqi archaeology.
• ~500 BC — Greek/Roman tabula: direct precursor to modern Backgammon.
• ~600 AD — Persian Nard: closely resembles modern Backgammon.
• 1745 — Modern rules published in Edmund Hoyle’s gaming books.
• 1920s — doubling cube invented. Adds gambling layer to the game.
• 1960s — backgammon boom in America. Becomes a coffee-shop game.
• 1990s — TD-Gammon AI: Gerald Tesauro’s TD-Gammon learns superhuman play through self-play (precursor to modern reinforcement learning).
• 2000s+: backgammon thrives online with massive multiplayer platforms.

Common mistakes

• Leaving blots randomly. Every blot is a risk. Calculate the hit probability.
• Ignoring back checkers. Stranded back checkers cost games.
• Bearing off carelessly. Exposing blots while bearing off can cost a winning position.
• Not maintaining priming. Letting your prime structure crumble before opponent escapes.

Variants

• Standard Backgammon. 15 checkers, 24 points. The classic.
• Nackgammon. Starting position varies; same rules.
• Hyper-Backgammon. 3 checkers per side. Faster, more chaotic.
• Nard. Persian variant — different starting position.
• Trictrac. French scoring-based variant.

FAQ

• Q: How many checkers per player? A: 15 each.
• Q: What’s a “blot”? A: A single checker on a point. Vulnerable to being hit.
• Q: When can I bear off? A: Once all 15 of your checkers are in your home board (points 1-6 for white).
• Q: Why doubles count double? A: Rolling doubles (e.g. 4-4) lets you move FOUR 4s instead of two. Significantly accelerates the game.

For other classic board games, try Chess, Checkers, Reversi, or Mancala.