The doubling cube is one of the most misunderstood tools in backgammon. Many beginners either never use it or don't fully understand how it works. This guide covers everything from absolute basics — what the cube is, how it works, and when to use it.
What Is the Doubling Cube?
The doubling cube is a six-sided die marked with the numbers 2, 4, 8, 16, 32, and 64. Unlike regular dice, you don't roll it — you turn it to increase the stake of the current game.
Important: The doubling cube is used in standard (international) backgammon. Iranian backgammon (Teh-Toghari) typically doesn't use it. AsNard supports both styles.
What Do the Numbers Mean?
The cube determines how many points the game is worth. It starts at 1 (winner gets 1 point). Each time the cube is turned, the value doubles:
| Cube Position | Point Value | Example |
|---|---|---|
| Game start | 1 point | Normal win = 1 point |
| First double | 2 points | Worth 2 normal wins |
| Second double | 4 points | Worth 4 normal wins |
| Third double | 8 points | One game = eight! |
| Maximum | 64 points | Rare but possible |
The higher the cube, the more pressure on both players. One wrong decision at a high cube level can decide an entire match.
Basic Cube Rules
- Start: The cube sits at the center or side of the board showing 64 (meaning 1)
- Doubling: On your turn (before rolling), you may turn the cube and offer the double
- Accept: Your opponent may accept and play continues at double stakes
- Drop: Your opponent may drop (resign) and lose 1 point at current value
- Cube control: Only the player who last accepted a double can double again
Real Game Example
You're in a 5-point match tied 2-2. You double, putting the cube at 2. Your opponent accepts. The winner of this game gets 2 points — one big step toward victory.
Now imagine the cube is at 4 and your opponent offers a double. You're in a weak position (~20% win chance). If you drop, you lose 4 points. If you accept and lose, you lose 8 points. Dropping is the smart choice here.
When to Double
Three key questions before every double:
- Is my win chance above 70%? If yes, doubling is logical
- Will the opponent likely drop? If your position is dominant, they might fold and you win 1 point
- If they accept, can I still win? If unsure, be cautious
Rule of thumb for beginners: When you think "I might win" — don't double. When you're sure "I should win" — do double.
When to Accept a Double
Accepting is harder than offering. Ask yourself:
- What's my win chance? Above 25%? Accept. Below 20%? Better to drop
- What's the match score? If you're behind, taking more risk makes sense
- Will I regain cube control? If you accept, you own the cube and can double later
Common Beginner Mistakes
- Never doubling: The cube is a weapon — not using it weakens your game
- Early doubling: Doubling in the first 5 moves is almost always wrong
- Accepting everything: Some positions are so bad you should drop
- Fear of high cubes: A cube at 16 or 32 is scary but sometimes worth the risk
The Cube in Match Play
In match play (5, 7, 9-point matches), the cube gets more complex. The famous Crawford Rule states: when a player is one point away from winning, the cube is not used in the next game. This keeps the match fair.
After the Crawford game, the trailing player can double earlier to try to catch up. This advanced strategy is covered in our dedicated article.
Don't fear the cube — embrace it as an opportunity. Practice on AsNard and you'll gradually develop a feel for when to turn it. Start with practice games against the computer or friends to build confidence.
