Backgammon

"I AM giving up the game, Holmes - that man Moriarty has the devil's own luck."

Holmes stopped his microscopic study of some strange-looking cigarette ash and studied me for a few moments. "You are strangely irate this evening, my good doctor. Pray show me the position that has caused you to utter such a rash statement."

I quickly got out our board and set up the position that you see above. "Black had just thrown a series of doubles finishing with 44, making his 5-point. I threw my very best, a double 2, hitting Moriarty's last man and making my own 4-point. Alas, his position was still so strong that I had to drop his redouble."

"My dear Watson, I think that once again you have let emotion rule your head. Whilst this is not an easy take it is nevertheless a take. In 11 rolls out of 36, black enters and is forced on 5 of those rolls to break his prime. Of his entering rolls, only 25 is really good for him. Even if he doesn't enter you can probably hold your position for one more roll, giving Moriarty another chance to enter and break his prime. Neither side will win many gammons. I would estimate that you will win at least 25 per cent of the time. Lastly, never forget the value of the cube in positions such as this - it would have given me great pleasure to hear that Moriarty had had to drop a redouble to 8."

As ever, my friend's analysis was clear and succinct. I resolved that it would be he, and not I, who would take on the fiendish professor in the high-stakes Diogenes Club chouette the following night.