Back games are among the most interesting categories of backgammon positions. (Some enthusiasts, like myself, consider them by far the most interesting.)
Obvious plays are often wrong and counter-intuitive ideas abound. Some real insight and experience is often needed to find your way to the right play.
Try your hand at these two examples, but watch out! The right answers may require a little thought.
Black to play 3-2.
Don't make blocking points against a back game unless there's some chance of actually blocking your opponent.
The obvious play is 13/8, filling in the last blocking point in Black's prime. The blot left on the 13-point is of no consequence in view of White's weak board. However, Black has no need for the 8-point. White has plenty of time to maneuver and build his board with the four spare checkers on the 13-point and the 8-point, plus the spare on the 20-point which can be released with any 5 or 6. Black will find himself needing to clear the 8-point pretty soon, at a time when White's board is likely much stronger than it is now.
Instead, Black needs to address the real problem in his positionthe open 3-point. It's true that Black has several builders bearing on the 3-point, and each turn he's a little less than even money to make the point naturally. But it's a disaster for him if he never makes the pointthen White is in effect playing a 2-3-5 backgame, and Black will be leaving plenty of shots when White's board may be strong enough to win.
The right play is to go ahead and slot the point now with 8/3! Not only is White unlikely to hit, but most of his hits are too dangerous in light of his weak board. He'll be better off passing on the hit and just building his position. In effect, Black gets a free shot to build the most critical point available.
Black to play 5-4.
This is not a particularly difficult problem, although many players will get it right for the wrong reason.
The classical approach to this kind of position was to play 13/8, 6/2*, with the idea that if you were hit, you would fall back into a strong back game, while if you were missed, you might even be able to win going forward. Thus this represented a "two-way" play: good winning chances no matter what course the game took.
The play is correct, but the reasoning is a bit different. In fact, Black has virtually no chance of successfully timing a back game from here, whether he gets more checkers hit or not. Before White starts to break his prime, he has to move his rear two checkers all the way around the board, then bring in the checkers from the midpoint. That represents a lot of turns, probably 10 at a minimum. There's almost no way Black's position can hold up for that length of time.
In fact, 13/8, 6/2* is just a straightforward attempt to win with a front game. Black is rooting for a fan, after which he can make a good board pretty easily, then root for some aces, deuces, and sixes to jump White's prime. It's something of a long shot, but much more likely than winning a busted back game. When the timing to hold a back game just isn't there, sometimes your best chance is just to attempt to win going forward. These can be hard plays to make since the chance of success seems so small. But the chance of success is small for any game plan, so just go ahead and follow your logic.
Next time: Cube Based Checker Plays