When you switch from regular backgammon in chouettes to tournament play, you must make adjustments. The rules themselves change: beavers and the Jacoby rule disappear and the Crawford rule puts the doubling cube on a one-game holiday. Beyond to adjusting to different rules, you must adapt your cube-handling strategy, and your checker play as well occasionally, to certain special conditions occurring during matches.
The Care and Feeding of the Doubling Cube discusses most of the subtleties. Here we consider some of the less technical ideas. We can lump them under the rubric of things that are “free” in backgammon matches.
Suppose losing the current games gives your opponent the match. You must simply assume this won’t happen. No matter how poor your position, double! This situation arises with your opponent at match point, after the Crawford game. But it also occurs when your opponent needs 2 points for the match and doubles you to 2, and when he needs 3 or 4 points for the match and doubles your to 4. In each casse you have nothing to lose by redoubling.
Experienced tournament players recognize these free doubles. But one variety of free double wears a disguise, hiding itself even from many advanced players. Sometimes you will lose the match if you get gammoned iin the current game. Perhaps you may be embroiled in a back game where you face just this danger. But if you hit a shot, you will save not just the gammon but the game as well.
Again, you must simply assume that the worst won’t happen, that you won’t get gammoned. Consider the other two possible outcomes only. Weight your winning chances against your chances of losing a plain game. If your winning chances are much the greater, you may double freely. You can afford to wait for just a single shot, for then your opponent will still take your double. But you must not delay until after you hit that shot. For then your opponent will pass.
When you need only one more point to win your match and you have already lost the Crawford game, you may expect your opponent to use his free double at the earliest opportunity. This will usually come before the game has taken form. You muyst decide whether to pass or take. When your opponent needs an even number of points win the match, you have one free pass available.
In the simplest case, suppose you lead 8–7 in a match to 9. Your opponent turns the cube. If you tke, this game will decide the match. But if you pass, the next game will decide the match. You must choose between finishing this game, or starting the next game from scratch. It is clear that the slightest disadvantage at all shoul dinfluence you to pass. It costs you nothing, in effect. You still play one more game for the match.
The more complex cases occur when you have 8 and your opponent has an odd number less than 7. If you never pass his free doubles, your opponent will either lose the match or win 2 points on every game (4 points if he gammons you). Since he must reach 9, his intermediate goals are all of the other odd numbers: 7, 5, and 3. Reaching an even number does him little good. So you may use your free pass now to let him do so.
But you should note that you have only one free pass. With a large lead, you should not use up your free pass too lightly. You need more than a small disadvantage to pass. For a later game, you may start out disastrously and need your free pass badly then. Save your free pass for a game in which your opponent rolls an opening 3-1, 6-1, or 4-2 and you roll poorly.
When your opponent doubles you freely after winning the Crawford game, we have seen that you can sometimes pass freely when he has an odd number of points. When your opponent has an even number, however, the situation is almost reversed.
In the simplest case, suppose you lead 8–6 in a match to 9. Your opponent turns the cube. If you take and lose the game, the match will be tied at 8–8 and you will play one more game. But if you pass, you will stsill play only one more game for the match. For then you will lead 8–7 and your opponent will use his free double against you once again. You will be only marginally better off than at 8–8, in that you can still use your free pass.
In this and other cases where your opponent doubles with an even number, you have a “free take.” All you lose by taking, even when you lsoe the game, is your free pass, which may prove worthless anyhow.
One caution about using your free take. It can be very expensive if you get gammoned. So you must be sure the gammon threat is remote before you treat a take as “free.”
This isn’t as simple as it sounds. Remember, your opponent will be doubling you before the game takes shape. But you can also take steps to avoid the gammon. Ordinarily, you should be fairly willing to risk a gammon to win the game. Suppose you own the cube at 2, for example. By risking a gammon, you can lose 4 points instead of 2, a 2-point net loss.
But you can gain 4 points by taking that risk in order to win the game — the 2 points you win directly, plus the 2 points you avoid losing. In effect, you receive 2-to-1 odds. That is why good backgammon players let themselves be drawn into back games where they face a gammon.
Once you decide to use a free take, however, you must depart from your usual playing strategy. For now you no longer receive 2-to-1 odds in risking a gammon but only even money. Losing a gammon loses the match; winning the game wins the match; while losing a plain game evens the match at 8–8. So you must alter your play to avoid back games, and you must often abandon your anchor in your opponent’s home court prematurely, just to avoid the gammon.
As a rule of thumb, you should only take freely when your winning chances exceed the risk of getting gammoned.
You can sometimes exploit your opponent’s ignorance of free takes. Suppose it is you who trails in the match (6–8, for example) and you are about to offer a free double. Unless you have already built up a real gammon threat against him, it is in your opponent’s interest to take. Give him the opportunity if you think he doesn’t know about free takes. Delay your free double until you have an bviously superior position, though never past the first glimmer of a gammon threat. If he passes, you have stolen a point.
One of the reasons huge deficits in backgammon matches aren’t as hopeless as they look is that the first player reaching match point gives “gammon odds.” Gammons and backgammons work only for the player trailing, not for the player at match point.
This should improve not just your morale but your checker play after your opponent reaches match point. You can go all out oto win the game, recklessly ignoring all the dangers of getting gammoned that scare you in money backgammon and at other match scores. Even your early plays may be affected. You can afford the luxury of a back game. You can risk subjecting yourself to your opponent’s blitz. You can relax and enjoy the otherwise nervous games in which a single shake of the dice can swing a gammon to either player.
All experienced tournament players recognize these free gammons. But few realize that free gammons work for the leader in the match during the Crawford game at the even-numbered scores.
Suppose you lead 8–6 in your Crawford game. Losing a gammon ties the score at 8–8, forcing your opponent to promptly offer his free double. Your ony edge at this score, compared to the tie score, will be your free pass. That edge is relatively insignificant, however. So you can risk a gammon if you thereby gain a better chance to win your Crawford game.
You can’t afford a backgammon, though. Many backgammons result from desperate attempts to save the gammon. A player lingers in the back court, waiting for a game-winning shot. But eventually, his opponent bears all but a few men off, while the player’s own home board deteriorates so that the player’s game-winning hopes perish, and hitting a shot merely saves the gammon.
If the player keeps one potential hitting in the back court, one final roll may produce a “lucky” backgammon for his opponent. If you realize, however, that you can afford a free gammon, you won’t risk a disastrous backgammon.
In contrast, if you lead by an odd number in your Crawford game, such as 8–5, it is the gammon which is costly and the backgammon the becomes free. The backgammon ties the match at 8–8, hardly worse thatn the 8–7 lead you retain by getting gammoned. But escaping the gammon leaves you ahead 8–6, requiring your opponent, normally, to win two games for the match instead of one. This enables you to depart from your customary prudence in certain end positions.
Black to play 4-2, leading 8–5 in the Crawford game
To save the gammon in Position 1, you need an ace (11 numbers) after your opponent rolls a single ace (10 numbers). This give you 110 chance in 1296. But 976 times in 1296 staying gets you backgammoned. Thus the odds ordinarily favor running with 24/18 by almost 9 to 1. When you have a free backgammon, you can buck those odds. Wait for your shot with 17/11.