Match play
Most serious backgammon is played as matches to a set number of points. The score changes what the cube and gammons are worth, so the best play in a match can differ from the best play for money.
How a match is scored
A match is a series of games played until one player reaches an agreed number of points. Each game is worth points like this:
| Result | Points |
|---|---|
| Single game | 1 × the cube value |
| Gammon | 2 × the cube value (the loser has borne off no checkers) |
| Backgammon | 3 × the cube value (as a gammon, with a losing checker still on the bar or in the winner's home board) |
| Double refused | The cube value before the double |
So if the cube is on 2 and you win a gammon, you score 4 points. If you double from 2 to 4 and your opponent refuses, you score 2. The doubling cube page explains doubling, taking and dropping in detail.
Players usually describe the score by how many points each side still needs, rather than how many they have. In a 7-point match where you have 4 and your opponent has 5, you are "3-away" and they are "2-away", written 3-away/2-away. This makes positions easy to compare across match lengths: the situation at 3-away/2-away is the same whatever the length of the match.
Match length
Any length is possible. Short matches of 1, 3 or 5 points are popular online. Club and tournament matches are often 7 to 11 points, and the main events at major championships are longer. Odd lengths are traditional.
Longer matches favour the stronger player, because luck has more time to even out. A 1-point match is a single game with no cube decisions at all, since the first win ends it. A 3 or 5-point match brings in the cube and gammons but can still be decided by one big game. In Backgammon Lounge you can play the computer in single games or in matches to 3, 5, 10 or 15 points; see play vs computer.
The Crawford rule
Without a special rule, a trailing player would double at every opportunity once the leader was one point from winning: the leader wins the match with any game, so a double costs the trailer nothing extra. That would make the leader's position much weaker than their score deserves.
The Crawford rule fixes this. The first time either player reaches one point short of winning (for example 6 points in a 7-point match), the next game is played with no doubling at all. That game is the Crawford game. It happens only once per match. The rule is named after John R. Crawford, an American bridge and backgammon player, and it is standard in tournaments and online.
In the Crawford game, gammons matter a lot to the trailer. The leader needs just one game; the trailer often needs more than one point, so a gammon can be worth much more to them than a single win. The leader, in turn, should be careful to avoid losing a gammon.
After the Crawford game
If the trailer wins the Crawford game, the match continues and the cube comes back. These are the post-Crawford games. The leader still needs only one point, so a double never helps them: the leader should never double. The trailer, on the other hand, has nothing to lose by doubling, since losing any game already loses the match. So the trailer normally doubles at the first opportunity, doubling the stakes of a game they would otherwise have to win anyway.
Free drops
The clearest case of a free drop is the score 1-away/2-away: if the trailer doubles and the leader refuses, the score becomes 1-away/1-away and the next game decides everything. If the leader takes, this game decides everything. Either way the trailer needs one more game win, so the leader can refuse the first double whenever the current game looks worse than a fresh start.
Double match point
At 1-away/1-away, called double match point, the next game decides the match and the cube has no use at all. Gammons do not matter either. Only winning the game counts.
Gammons and the score
In a money game, a gammon is always worth twice a single win. In a match its value depends on the score and on what the cube is. A few general ideas:
- Dead gammons. If a single win at the current cube value already wins the match, a gammon adds nothing for that player. Play purely to win the game.
- The trailer gains from gammons. A player who needs several points benefits more from a gammon than a player who needs few. This affects checker play too: the trailer can play more boldly for a gammon.
- The leader fears gammons. A lost gammon can turn a comfortable lead into a deficit, so the leader often plays more safely, especially when the cube is high.
- The cube level matters. When the cube is high enough that a single win ends the match for one side, every gammon decision changes for that side.
These ideas change cube decisions: a position that is a take for money may be a drop when gammons are very costly at the score, and the other way round.
Match equity
The key idea in match strategy is match equity: your chance of winning the whole match from a given score. Being 2-away against 4-away is clearly better than the reverse, but by how much? Match equity puts a number on it.
Players and programs use a match equity table, which lists your chance of winning the match from every score up to some length, assuming two equally strong players. Early tables were worked out by hand from experience and modelling; modern ones are calculated from huge numbers of games played by strong backgammon programs. The tables in use today agree closely with each other.
With a table you can work out cube decisions at any score. To decide whether to take a double, compare your match equity if you drop (you lose the current cube value now) with your match equity if you take and then win or lose the game, possibly with gammons, at the higher cube value. This gives the take point for that score, the winning chance you need to take. It is often different from the 25% that applies in money games, sometimes much lower and sometimes higher.
You do not need to memorise a table to play matches well. Knowing that the score changes the value of gammons and the cube, and asking "what do I need to win from here?", already improves your decisions a lot.
Matches vs money games
A few rules from money play do not apply in matches:
- No Jacoby rule. Gammons count even if the cube has not been turned.
- No beavers. Immediately redoubling while keeping the cube is a money game option only.
- No automatic doubles. Opening ties are simply rolled again.
- The cube is capped in practice. There is no point doubling beyond what your opponent needs to win the match, so cube values stay low.
Matches reward a clear head about the score. The best way to learn is to play some: start a match against the computer and watch how the Crawford game and the post-Crawford doubles change your choices. For terms you meet along the way, see the glossary.
Questions
What is the Crawford rule in backgammon?
When one player first reaches one point short of winning the match, the next game is played without the doubling cube. That single game is the Crawford game. After it, the cube is back in play for the rest of the match.
Why are backgammon matches usually an odd number of points?
It is a convention rather than a rule. Matches to 5, 7, 9 or 11 points are common in clubs and tournaments, and any length is allowed.
Does the Jacoby rule apply in matches?
No. The Jacoby rule, which stops gammons counting until the cube has been turned, is used only in money games. In a match every gammon and backgammon counts, cube or not.
Should the trailing player double right away after the Crawford game?
Usually yes. The leader cannot gain anything from the cube, because a single game win already takes the match, so the trailer loses little by doubling early. There are a few exceptions, such as when the leader has a free drop.
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