Games: Backgammon

This deceptive position occurred in my chouette the other evening. Black is on roll and is considering a double. What is the correct cube action for both sides?

As with any position, the first thing to do is the pip count. Black's count is 72. And lo and behold, White's pip count is also 72. Based on the race alone Black should not double - but what about the other elements of the position?

There are three things that Black should consider. First he is in a good attacking position. Many small numbers, eg 32, 42, make his 4-point. With numbers like 52 he will hit loose on the 4-point and make his 1-point. If White fails to enter first time he will be lost.

The second point is that in the race Black needs only three short cross- overs (a cross-over is the movement of a man from one quarter of the board to the next) before he can start to bear off his men. White, on the other hand, needs five cross-overs before he can start his bear-off.

Finally, even when White does start to bear off his men his home board position is far from ideal. When you start a bear-off you want most of your men on the higher points. Here White already has five men on his 2-point, which will lead to an inefficient bear-off.

All three of these points favour Black and it should be apparent that he has a strong double. What is surprising is that White's position is in fact so bad that he must drop the double - he needs too many things to go right for him, and he will win from this position only 20 per cent of the time. Beware of evaluating such positions on the race alone - you must consider the whole board. In the game from which this position was taken, Black doubled, and White took and promptly got gammoned. All races are not equal.