Backgammon

Last week we introduced the concept of Woolsey's Law of Doubling, (roughly, "If in doubt, double") Now let's look at a practical example. With a man on the bar you are on roll as Black in the above position. Should you double? Should White take or pass?

I was in the box with a partner when this position arose in a six-handed chouette at the Double Fives club (with six or more, it is common for the box to take a partner).We then discussed whether to double.

Certainly this position is very volatile. By our next roll we could either have lost our market - reached a position where our opponents would immediately drop a double - or be in trouble ourselves. Consider, for example, the sequence 6,5 for Black followed by 6,5 for White, when it is White who will have lost their market.

In the start position nearly all numbers play well. 4s hit from the bar. 2s, 5s and 6s can be used to hit on the 5-point. 1s and 3s are not so good, but double 1 and double 3 both play well. If we hit one of White's men and they fail to enter we will definitely have lost our market. Now apply Woolsey's Law: if Black doubles should White take? Although we thought our opponents would take, White is going to lose a lot of gammons and that may just push the decision towards a drop. This meets Woolsey's key criterion: we're not totally sure it is a take - so we must double!

Double we did and White accepted the cube. We were rewarded for our aggression by rolling 4,4. This was played Bar/21*, 13/9/5*/1* putting three men on the bar. White stayed on the bar and we easily won a gammon. Later analysis using Jellyfish showed that with White owning the cube, Black wins only 51 per cent of the time but 70 per cent of those wins are gammons. This confirms the correct action in the initial position to be double/take.