Bill Robertie’s Blog

Leave Your Anchor or Not?

Jun 1, 2018 | Backgammon Problems: Holding Game

White – Pips 105 (+6)

Black – Pips 99 (-6)
Black to Play 5-2 read more…

Bearing in Against the Ace-Point

May 15, 2018 | Backgammon Problems: Ace and Deuce-Point Games

When bearing in against an ace-point or other low anchor game, you generally have two goals in mind. The first is safety; you want to create formations that are less likely to leave blots as you bear off. The second is winning a gammon; you’d like to maximize your gammon chances if you can.

It’s usually good practice to look at the gammon chances first. If your gammon chances are either very large or very small, then it’s not likely that any play you make will affect them enough to matter. In those situations, you just make the long-run safe play, whatever that might be. But if the gammon is up for grabs (which in practice means gammon chances in the 15% to 40% range) then you may need to look for riskier plays which win more gammons at the cost of some extra losing chances. Typically, these plays involve piling checkers on the 6-point and 5-point, hoping to hold the prime as long as possible, or bearing off checkers rather than clearing a point.

Handling 6-Primes

May 1, 2018 | Backgammon Problems: Priming Games

A full six-prime is the most powerful formation in backgammon. A checker trapped behind a six-point prime can’t escape. To win, the trapped player has to somehow force his opponent to break his prime.

Although building a full prime is the strategic goal in many positions, we don’t actually see too many six-primes over the board. Often, the mere threat of making a six-prime will force a double and a drop. Although six-primes aren’t common, they are governed by their own set of strategic principles. Let’s take a look at a few.

Playing Efficiently

Apr 15, 2018 | Backgammon Problems: Middle Game

White – Pips 137 (-13)

Black – Pips 150 (+13)
Black to Play 4-1Here’s a problem of a familiar sort. Black has been steadily building his front position, while White has tossed in a 5-3 and a 6-5. White’s last roll of 6-5 completes the escape of his back checkers, but leaves him with a huge stack on his midpoint. Now that White has escaped entirely, Black has to leave his front position alone and start mobilizing the back men. He has two choices: 24/20 11/10, or 24/23 13/9. (24/23 11/7 is all right as well, but 13/9 yields a slightly more active distribution.) Which is best?