The gammon price is one of the most important — and most misunderstood — concepts in advanced backgammon strategy. It describes how much extra equity you gain (or risk) from a gammon outcome, and it determines whether you should play aggressively for a gammon or consolidate for a safe single win. Mastering gammon price transforms your cube decisions and positional choices at all levels of the game.
Key Takeaways
- Gammon price is the equity value of winning a gammon relative to a single win — it's always positive for the attacker
- In money games, a gammon is worth 1 extra point; the gammon price depends on the cube level
- In match play, gammon price varies dramatically by score — sometimes it's enormous, sometimes it's zero
- When gammon price is high, you should play more aggressively and risk leaving shots to create gammon threats
- When gammon price is low (e.g., 2-away match scores), playing safe for a single win is always correct
- Both sides have a gammon price — the losing side also has a gammon-save price worth considering
What Is the Gammon Price?
In backgammon, a gammon (winning when your opponent has borne off zero checkers) is worth twice a single win. A backgammon (opponent still has checkers on the bar or in your home board, with zero borne off) is worth three times a single win.
The gammon price measures how much additional equity the possibility of a gammon adds to your position — and therefore how much risk you should take to preserve or create gammon threats.
The Core Insight
In most positions, you face a tradeoff: you can play safely (lower gammon chance, lower gammon-loss risk) or aggressively (higher gammon chance, but potentially leaving shots that increase your own gammon-loss risk).
Gammon price quantifies which choice is better.
Calculating Gammon Price in Money Games
In a money game with the cube at 1, the payoff structure is:
| Outcome | Points Won/Lost |
|---|---|
| Win single | +1 |
| Win gammon | +2 |
| Win backgammon | +3 |
| Lose single | -1 |
| Lose gammon | -2 |
| Lose backgammon | -3 |
If you double to 2:
| Outcome | Points Won/Lost |
|---|---|
| Win single | +2 |
| Win gammon | +4 |
| Lose single | -2 |
| Lose gammon | -4 |
The Gammon Price Formula (Money Game)
$$\text{Gammon Price} = \frac{G_w - G_l}{1 + G_w + G_l}$$
Where:
- $G_w$ = your gammon win probability (as a fraction)
- $G_l$ = your gammon loss probability (as a fraction)
This gives you the adjustment to your take point due to gammon possibilities.
Simplified Gammon Price Table (Cube at 2, Money Game)
| Your Gammon Win % | Your Gammon Loss % | Adjusted Take Point |
|---|---|---|
| 30% | 5% | ~19% (lower than 25% basic take) |
| 20% | 10% | ~24% |
| 15% | 15% | ~25% (neutral — gammons cancel) |
| 10% | 25% | ~29% (higher than 25% — gammons favour defender) |
| 5% | 35% | ~33% |
Key insight: When your gammon win probability exceeds your opponent’s, the gammon price works in your favour — your opponent needs more wins to justify a take. When your opponent has more gammon wins, the price works against you.
Calculating Gammon Price in Match Play
In match play, the gammon price is not fixed — it changes with every score change. This is because gammons have different match equity values at different scores.
Examples of Match Score and Gammon Price
| Score (you-away / opp-away) | Your Gammon Price | Their Gammon Price |
|---|---|---|
| 5-away / 5-away | ~0.5 | ~0.5 |
| 3-away / 3-away | ~0.4 | ~0.4 |
| 2-away / 4-away | ~0.0 | ~0.7 |
| 4-away / 2-away | ~0.7 | ~0.0 |
| 2-away / 2-away | ~0.0 | ~0.0 |
Why Gammon Price Is Zero at 2-Away
When you’re 2-away (one win ends the match), a gammon gives you the same result as a single win — the match ends either way. Therefore your gammon price is zero: there is no benefit to winning a gammon vs a single win.
This completely changes your strategy at 2-away scores:
- Never risk a gammon loss in order to increase your gammon win chances
- Play conservatively — just win the game
High Gammon Price Scores
When you’re 4-away or more and your opponent is 2-away, your gammon price is very high — winning a gammon skips you 2 points instead of 1, dramatically changing your match equity. In these situations, playing aggressively for gammon is almost always correct.
How Gammon Price Affects Positional Play
High Gammon Price: Play Aggressively
When your gammon price is high (early in a match, or at deep scores in your favour), you should:
- Close your home board faster — even if it means leaving a loose checker
- Attack early — hitting blots and building the home board creates gammon threats
- Delay bearing off — sometimes it’s correct to wait and trap opponent’s checkers rather than bearing off immediately
- Take cube risks — accept doubles that create gammon opportunities even at some risk
Low/Zero Gammon Price: Play Safely
When your gammon price is near zero (at 2-away, or if you have very few gammon win chances):
- Consolidate — don’t leave blots chasing gammon threats that aren’t there
- Bear off efficiently — focus entirely on completing the bear-off cleanly
- Refuse gammon risks — don’t accept cube positions where gammon loss is likely; the gammon-win upside doesn’t exist
Gammon Price and Cube Decisions
The gammon price is the primary reason cube decisions in backgammon are more complex than a simple win-probability comparison.
Adjusted Take Point
In a money game with no gammons, the basic take point is 25% wins. With gammons:
$$\text{Adjusted Take Point} = 25% - \frac{G_w - G_l}{4}$$
Where $G_w$ and $G_l$ are the gammon win/loss probabilities for the side considering taking.
If you’ll win gammons 20% of the time and lose them 10% — your take point drops to roughly 22.5%. You can take with less winning chances because your gammons more than compensate.
If you’ll win gammons 5% and lose them 25% — your take point rises to roughly 30%. You need more winning chances to compensate for the gammon loss risk.
The Gammon-Save Concept
The gammon-save is the mirror of gammon price: it describes how much equity you gain by avoiding giving a gammon, even if you lose the game.
When your opponent has a powerful attacking position and you’re facing a likely gammon, sometimes the correct play sacrifices the game faster to avoid a gammon. This is called playing for a gammon-save.
When Gammon-Save Matters
- You’re in a back game or trapped position with multiple checkers behind a prime
- Your opponent has a strong home board and closed position
- The cube is already at 2 or 4 — losing a gammon costs double or quadruple
- In match play, losing a gammon vs a single might drop your equity from 20% to 5% instead of 20% to 15%
Gammon-Save Strategy
- Bear off as quickly as possible — don’t advance checkers that could give gammon material
- Sacrifice position in the outfield to run home board checkers off faster
- Consider unusual bear-off plays that sacrifice pip efficiency to avoid the gammon
Practical Rules of Thumb
| Situation | Gammon Price Rule |
|---|---|
| Early in a long match (5+ away) | Play for gammon aggressively |
| Leading in match, 4-away vs 2-away | Very high gammon price — attack freely |
| 2-away (one win ends match) | Gammon price is zero — play safe |
| Behind in race but have good home board | Maintain home board for gammon threat even if racing behind |
| Money game, cube at 2 | Gammon win = +4 pts; gammon loss = -4 pts; price is symmetric |
Frequently Asked Questions
Does gammon price change when the cube is higher?
In money games, the gammon price stays proportionally the same at any cube level because all values scale together. In match play, the cube changes equity in a non-linear way, making gammon price analysis more complex at each cube level.
Should I always play for gammon if I have a gammon threat?
No. Play for gammon when the gammon price justifies the risk — that is, when your gammon win equity exceeds the cost of the additional risks you take. If going for gammon means leaving shots that could result in your own gammon loss, calculate carefully.
What is a “gammon-heavy” position?
A position where gammons are likely for the winning side — typically, when the leading player has a strong closed home board and multiple attacking threats. Such positions have high gammon prices and should be evaluated differently from racing positions.
How do I learn to evaluate gammon price at the board?
Memorise a few key match equity values (especially 2-away positions where gammon price = 0), and use your feel for gammon frequency in different game types. Software analysis after games shows exactly what XG calculates for gammon price in each position.
Is gammon price the same as gammon equity?
Not exactly. Gammon equity is the raw equity value of your gammon win probability. Gammon price is the net effect of both your gammon win and gammon loss probabilities — it’s the net gammon impact on your position.
Further Reading
- Gammon and Backgammon Wins — How gammons are scored
- Doubling Cube Strategy — How gammon price affects cube decisions
- Backgammon Match Equity — Match equity table and score-based decisions
- Jacoby Rule — How Jacoby affects gammon value in money games
- Backgammon Strategy — Full strategy overview