Backgammon

HERE'S A complex position from this year's World Championship final. Black (Elliot Winslow) and white (Michael Meyburg) are tied at 5-5 in a match to 25 points. Should Winslow double; should Meyburg take?

This is an unusual sort of position and one that is difficult to evaluate. One aspect that should never be ignored is the race. Here black has a healthy 103-139 lead that should make him at least think of doubling. Secondly, black will note that most of his numbers play well. All numbers other than sixes can be used to cover at least one blot.

Is the position volatile, as in, might black have lost his market by the next roll? Yes, it is. Any sequence where black makes another point in board and white fails to enter would give black a position where white could not afford to take. Is the position gammonish? Again the answer is yes - indeed later analysis shows that fully two-thirds of black's wins are gammons. All in all this looks like a powerful double.

Can Meyburg take despite the threats pointed out? From his perspective he has one of black's men trapped behind a four-point prime which could shortly become a five-point prime if he can make his three-point. If black fails to cover either of his home-board blots and white hits from the bar he will have equalised the position. Finally he also has a good possibility of anchoring on black's two-point that will give him a good defensive position for the endgame. Positions like this are scary because of the gammon threat but all in all white has enough chances to take.

In the event, both players evaluated the position correctly. Winslow doubled and Meyburg took. Winslow rolled 62 and played 16/10, 3/1. Meyburg failed to enter and Winslow won an easy gammon.