Tournament Rules - South Sinai Backgammon Tournament

Our original plan was to run a single-flight tournament for South Sinai. However, while speaking with local players and visitors from other countries, it became clear that nobody was familiar with the Doubling cube and the Crawford Rule.

When these elements were explained, the reaction often shifted from excitement to uncertainty.

As a result, we decided to introduce an The Cubeless Cup Flight, designed specifically as a welcoming entry point into tournament play. This flight will be played as single-point games with no doubling cube. It is an ideal way to experience a competitive tournament environment in a relaxed and accessible format.

For players who are ready to take the next step, full information about the Doubling cube and the Crawford Rule is available on this website. You have time to practice. In addition, experienced players and staff will be on hand during the event to explain how both work and to help anyone who wants to learn.

Introduction to the Doubling Cube in Backgammon

1. History of the Doubling Cube

The doubling cube is a relatively modern addition to backgammon, first appearing in the early 1920s in New York.

Before its invention, matches were played for fixed stakes, and there was no formal method to increase the value of a game mid-play.

The cube introduced dynamic stakes, allowing the player with an advantage to raise the stakes, creating a deeper strategic dimension.

Today, almost all competitive and tournament play uses the doubling cube.

2. What is the Doubling Cube?

• A six-sided cube marked with: 2, 4, 8, 16, 32, 64.
• Unlike dice, the cube represents the current value of the match, not a random roll.
• Control of the cube indicates which player has the right to offer the next double.
• In money play or match play, the cube allows the winner to increase the stakes at the appropriate moment, balancing risk and reward.

3. Basic Rules of the Doubling Cube

3.1 Starting the Game

→ The cube starts at 1, placed in the middle of the board.
→ Neither player owns the cube initially.

3.2 Offering a Double

A player may offer to double the stakes on their turn before rolling the dice.

The opponent must accept or resign:

Accept:

The game continues at double the current stake, and they now control the cube (only they can propose the next double).

Resign:

The player loses the current stakes.

3.3 Cube Ownership

→ After a double is accepted, the opponent owns the cube and is the only one who can double next.
→ Control alternates as doubles are offered and accepted.

3.4 Cube and Gammon/Backgammon

The cube multiplies the current match stakes:

→ Standard win = current cube value
→ Gammon = double the cube value
→ Backgammon = triple the cube value

3.5 Match Play vs Money Play

→ Money Play: Cube increases stakes in actual money; matches are usually one game.
→ Match Play: Cube can influence strategic decisions based on score, including Crawford Rule for match play situations.

4. Key Concepts for Using the Doubling Cube

4.1 Take Points

→ Take Point: The probability of winning where it's correct to accept a double.
→ Rough rule: If your chance of winning is greater than 25–30%, taking is often correct in money play.
→ In match play, match score matters, so take points shift depending on game situation.

4.2 Market and Cube Strategy

→ Market: When a player has the cube, the other player may offer a double once they regain control.
→
Cube Strategy: Involves evaluating:
- ◦ Probability of winning
- ◦ Match score
- ◦ Potential for gammon/backgammon

4.3 When to Offer a Double

Offer a double when:

→ You have significant advantage in position or board control.
→ Opponent has little chance to recover.
→ You want to pressure your opponent into taking a difficult decision.

4.4 When to Take or Drop

→ Take when your chance of winning is sufficient to make risk worth it.
→ Drop when the opponent has a clear advantage, and the risk of losing double stakes is too high.

5. Practical Tips for Beginners

• Start simple: Play with the cube in casual games without money at first. Focus on cube timing, not stakes.
• Observe opponents: Learn how experienced players judge positions for doubling.
• Use software: Online backgammon programs allow cube practice with feedback.
• Think in probabilities: Estimate winning chances roughly (high/medium/low) before doubling.
• Avoid automatic doubling: Doubling too early or too late can give away strategic advantage.
• Keep track of cube ownership: Forgetting who can double is the most common beginner error.
• Combine with pip count: Always consider pip advantage (checkers remaining to bear off).

6. Training Exercises

6.1 Solo Cube Practice

→ Play standard backgammon and practice offering doubles at the right moment.
→ Record outcomes and review decisions.

6.2 Pair Training

→ Partner up; one player controls the cube, the other focuses on take/drop decisions.
→ Rotate roles and discuss reasoning after each match.

6.3 Software Tools

Programs like Backgammon Studio, GNU Backgammon, or eXtreme Gammon provide:

→ Cube action advice
→ Analysis of mistakes
→ Real-time take points

6.4 Scenario Drills

Create specific board positions with known pip counts.

Practice cube decisions:

→ Should I double?
→ Should I take or drop?
→ What's my equity if I take?

7. Conclusion

The doubling cube adds strategic depth to backgammon.

Mastery of cube decisions is crucial in tournament and competitive play.

Start by understanding rules, then progress to probability assessment and practice scenarios.

Over time, cube strategy becomes an integral part of positional and tactical thinking.

The Crawford Rule in Backgammon

1. Purpose of the Rule

• The Crawford Rule exists to prevent the player who is ahead in a match from being unfairly pressured by the doubling cube in the final, decisive stage.

2. When the Crawford Rule Applies

• It is used only in match play, not in money games.
• Applies when one player is exactly one point away from winning the match.

Example:

→ Match to 7 points
→ Player A leads 6–4
→ Player B is behind by 2
→ The next game is the Crawford game.

3. How It Works

1. The game immediately following the situation described above is called the "Crawford Game."
2.
The doubling cube is not used in this game:
- ◦ Neither player may offer or accept doubles.
- ◦ The game is played at the current match stake, which is effectively "1 point."
3. After the Crawford Game, the cube is reintroduced for all subsequent games, if the match is not yet over.

4. Practical Example

• Match: First to 7 points
• Score: Player A 6 – Player B 4

Next game: Crawford Game

→ Players cannot double
→ Game played as normal
→ If Player A wins, match ends (7–4)
→ If Player B wins, score becomes 6–5; cube is now in play for the next game

5. Strategic Implications

Trailing Player:

→ Must plan cube strategy knowing Crawford could occur soon.
→ Cannot use cube to pressure the opponent in the Crawford Game.

Leading Player:

→ Focus on maximising chances in the Crawford Game, as it's their safest opportunity.

Post-Crawford Games:

→ Cube decisions become critical again.
→ The leading player may face doubles immediately in following games.

6. Summary

• The Crawford Rule is a fairness mechanism in match-play backgammon.
• Triggered: When a player is one point away from winning.
• Effect: One game is played without the doubling cube.

Doubling / Crawford Rules

Masters Only