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Doubling Cube Question

Today’s backgammon position deals with the question of the doubling cube. In the position below, it is a money game, and Black is on roll. Should Black double? If Black doubles, should White take?

Market Loser

There is no question that Black is winning here, and this is one of those positions where if Black rolls very well on his next roll he will “lose his market.” That means that he gets so good that when he doubles there is no chance to get White to take. For example, if Black rolls 6-1 or 4-4 he makes his 5 point and a full prime; or 6-5, 6-4, or 6-3 he escapes the back checker. And there are lots of other good rolls.

At the same time, Black may not rolls so well and white could get lucky and hit, make hit bar point, make Black’s 5 point, or make his own 3 point and have a pretty decent game. These kinds of positions are not easy, and what most of us do is try to make our best guess as to what is most likely to happen, and then guess what our opponent might do if doubled, and then make our decision.

Story Behind the Backgammon Position

This position came up in an actual backgammon game I was playing and I was Black and I thought about if for some time and decided it was very close. I then thought about what I thought my opponents would do if doubled, and I decided that there was a chance they might drop.

So I doubled and got dropped.

That made it an excellent double “over the board.”

Because I was not completely sure, I entered the position into GNUBG (backgammon program) and found out that it was not even correct to double! And it was a big take.

If you look at the GNUBG evaluation below, you will see that it is a huge error to double (.532) and also a pretty reasonable error to drop (.093).

The backgammon lesson here is clear…when in doubt, you are better off giving the cube than waiting…if you wait it might be a mistake, and if you cube it might be a mistake, but there is no chance for your opponent to make a mistake unless you cube!