Hi all,

Recently I played live backgammon in my city against the junior world champion 2014: a 5 point game, in a friendly tournament. On 2-2 score this position arose:


XGID=-a--BBBBBB--ba---b-bcAbbB-:0:0:1:00:2:2:0:5:10


The question is, as usual, what's the correct cube action, both white and black with explanation.

thank you.

So why is it no double? We are no bot, so we cannot scan all possible scenarios. So we do a little bird eye's view and feed that to our backgammon experience.

Black is stuck on the one point, and the only way to resolve this situation at the moment is to throw a three or 66. But with the majority of threes he will have to break his six prime, and prefer to move the blot on the 21point. With several dice combinations he has to give up his six prime, in particular 44. With two checkers on the one point (which might become three) he hardly has the better timing.
conclusion: just being unsure to double

I double. Lots of good rolls. hits, 3s, 6s. Bad rolls aren't terrible. I pass as white and go to the next game down 3-2. Who's the junior champ?

any other thoughts?

At money play, I definitely double, by Woolsey rule. I am unsure of the take, but I guess I would because 1) black has enough work to do to extract his back men without breaking his prime, 2) gammons seem fairly low, and 3) the recube potential looks good.

At 3 away-3 away, with few gammons, there is not very much match equity to gain or lose. So I would say no double because of the recubes.

As always, I would start by figuring out what I would do in a money game, then make adjustments based on what I would do at the match score.

For money, this looks like a trivially easy take. There are plenty of breaking numbers on the opening roll, and there will be more later. Breaking a 6-prime to a 5-prime doesn't guarantee a loss, of course, but once the prime breaks White is just one good sequence away from a recube.

The double looks like a tough call. Black is certainly a favorite, and the cube is in the middle, but he has plenty of work to do. I'd probably hold onto the cube for a turn, but I wouldn't be sure that I was making the right play.

At 3-away 3-away everything gets easier. Because a 1-0 lead to 3 isn't worth much, you double much quicker and you also drop quicker. So easy double now, but still clear take.

That was the point I missed.

Black was the junior world champ, and I was playing white.

In game he went in the tank for a while deciding whether to double or not, and finally he doubled. I ista-dropped the cube, thinking this way:

-He has a 6 prime
-He has all 3, all 5 all 6 (about even money) to keep the prime, and even if he brakes it's still a 5 prime.
-My home is incomplete with a high gap, with few numbers to cover it.
- taking and losing would be 4-2 crawford and serious score situation.
-Passing would cost me only 1 point at 3 away-3 away and, as Robertie said, it isn't worth much for him.


But somebody in the audience said, after my drop, "clear take" and I figured that if it ever was a take it was indeed very narrow. After the game I analyzed the position with XG and the response was solid double (almost -0.1 error not to double) and VERY HUGE take (passing is a -0.4 blunder).

Thanks for the comments

In anyway you seemed to be a proper match for the junior world champ.

This is an absolute double for money and most match scores for one very important reason. Many opponents will drop this cube.

Indeed. I took but considered it close, so my judgment was really way off. Perhaps a useful reference position.

To be sure to understand this position you have to manually rollout the position too see how things go.

Too simple to say "Easy take" without being experienced in the game IMO. The game in fact usually is PRATICALLY very tought for white to save/play: usually black rolls and doesn't break and run with the 21 blot and get the time to roll a 6 (no fear to be hit: only improves black timing) and then it's very hard for white to overturn the 4-2 crawford against a decent player.

And overall here white will lose, the 6 prime is very threatening. Passing and being 3-away 2-away is pratically simpler to play, you cancel a bad position, start a new game basically with a small disavantage.

I think, more generally, that the ones that serenely take position behind a 6 prime say too many times after losing "Why me? Must be the dice" because this are "conceptual positions": usually when you make a decision you are either wrong by a lot or right by a lot, almost never a in-between IMO.

To prove that the position may be trappy: simply shift the blot on the 20 point and the position became a double/ MONSTER DROP (-0.2 blunder)


Or if you shift the last points like this


It became a double and a narrow take (-0.06 "green" error if you drop, a human error I think) remember the original position, dropping is a gigantic -0.4 blunder.

Maybe the subtle difference is that in the original position duplication of trey may influence the outcome. But how many noticed the above differences?

The number of immediate break numbers is a very big part of the evaluation.

In your original position, Black breaks with 41, 42, 21, 54, 11, 22, and 44. That's 11 numbers, or almost 1/3 of his rolls.

In the first of your new positions (with the Black blot on the 20-point) Black breaks with 31, 53, 11, and 33. That's only 6 numbers, or 1/6 of his shots. That's a huge difference, so the position must be much stronger for Black than the original.