This fascinating decision arose during the opening game of a 5-point match I recently played against XG (extremegammon.com). XG is a must for any serious student of the game as it provides you with a world-class opponent 24/7 along with amazing analytical insights.
XG (yellow checkers) had cubed me a few rolls earlier and was now processing how to play this 5-1 roll. XG has secured a dominant position with a beautiful five-point prime and two of my checkers trapped behind it. Conventional wisdom suggests you should strive to leverage your assets to secure victory, and in this case that means retaining the prime and bringing the other checkers to safety. However, XG’s criteria is focused on match-winning chances rather than just how to win this particular game.
Many human players might just play 20/14 as it duplicates twos which brown may want to use to get to the edge of the prime, and also takes a vulnerable checker away from the imminent attack from brown’s stacked position on the 8,7 and 6 points (or represented as yellow’s 19, 18, and 17 points as shown in the diagram).
Surprisingly, XG decided to break the prime and hit both checkers with 7/2*/1*! This play reduces XG’s winning chances by approximately 8% but it raises the gammon rate by a massive 21%. With the game having been doubled, XG is pouncing on an opportunity to take a 4-0 lead in the 5-point match with the subsequent and advantageous Crawford rule in effect (no cube being allowed for one game when the leader is one point from victory). While other choices such as: 8/2*, 20/14, and 20/15 8/7 are all reasonable, XG’s aggressive alternative nets the maximum match winning chances by a small margin.
Frank has a passion for games and markets. He is a former winner of the Backgammon World Championship in Monte Carlo and has held the number one international ranking of both on-line and live match play.