Checker and cube mistakes in backgammon

We have received a number of playing positions from a player who has been playing and studying the game for many years. As with any player he also makes mistakes, after all making mistakes is a crucial part of improving your game. When he gets a position wrong he circulates it in order so that we and thus our visitors can learn from it.

It is Blacks turn – what is the correct cube action to take ?

1) Current match score

The score is 3-3 to 7. The gammonless doubling windows are virtually the same as in a real money game. If the cube goes to 2, gammons will play a much more prominent part in the game.

Factors to consider

• Score –2/-4: Match equity 66.4%
• Score –4/-2: Match equity 33.6%
• Score –0/-4: Match equity 100%

If the cube is turned, gammons will trade almost equally with wins.

2) Key elements of this position.

The race is almost even at this point. Black has a solid 5-prime with one white checker held back; White has a broken 5-prime with 2 black checkers back.

3) What actually happened at the table ?

Black offered a double and white passed

4) How does this position develop ?

It is a very close double and a trivial take. Black wins 63.6% with 17.6% gammons; White wins 38.4% with 11.3% gammons. Once the cube is turned, gammons become very important indeed . If it weren’t for this factor and that Black wins about 6% more gammons than White, then doubling would be considered a mistake.

5) What were the players thinking ?

This is a very interesting board position. The most significant thing that white missed is that he has only one checker back, and black has a some major work to do before white is fully primed.

Look at how black’s numbers play:

Nine numbers dance. After dancing, black is no longer the favorite. Admittedly, white’s aces are duplicated, but he will hit with every ace except 61.

If Black enters but cannot come up to the 20pt, he becomes a slight favorite, the game being about even with White being the owner of the doubling cube. He will have the same problem white has, namely getting a checker out from behind a 5-prime.

In fact, white’s only crushing roll is 55, which enters and creates a full prime.

It is very easy in backgammon to focus on only the best, or the worst, coming sequences. White in this case focused on his bad sequences. He could indeed end up struggling for a while with the straggler.

But he has the time to play in a constructive fashion for several rolls of the dice even if he is unable to escape. Black has limited ammo for an attack. He cannot slot the 2-point because of the strength of White’s board, and it will be difficult for him to extend the prime from the back.

White has a lot of options to get back into the game. Black can dance or enter deep and have trouble escaping. White can step up to the 23-point before Black can launch and effective attack. White can hit Black as he is trying to run for home. If Black cannot implement his main plan , ie trapping White’s straggler it will result in White being the favorite to win the game.

There are two questions one should ask themselves when in this position– how likely is it that you can get into a favorable game plan, and how favorable are those plans? Here White has several viable options , and all give him a good chance of winning.