Problem of the Week #125: October 30


Black on roll, center cube, score 0-0 in 7-point match.




Should Black double? If Black doubles, what should White do?



Note: All ‘cash game’ problems assume the Jacoby Rule is in effect. That is, you can’t win a gammon unless the cube has been turned.

I say no double/take.. Black is coming in way too fast and has no points in his outfield. It will be very hard for him to come in safely, and when he does get hit white has amazing timing and position over him.

You have a monster race lead and the only structure white has is from moving his pieces backwards to anchor on your 3, and if you hit him, it could turn into a complete disaster, so I don't know how this could be too weak to double. I also don't see how it could be too strong because your gammon rate isn't through the roof and you can still lose a reasonable amount of the time- it shouldn't be anywhere near 2:1. So double. I don't know if it's a drop or not- black has flexibility issues, and white still has reasonable board coverage, so getting home isn't a complete breeze, and the anchor to luckbox a shot at the end. When in doubt, take.

Double/take.

double/drop. 5 pt boards are tough

Black leeds by 181 – 121. White is outboarded 5:1. Black has 2, white 4 men behind. Both have outfield control, black has lost his 8 point. White holds an anchor, this is the one additional point he could make.
The position favours black. By now, there is no safe place for a blot, and a hit could be a nightmare, buying black enough time to run the stragglers to safety, collecting a few more gammons. The racing leed is crushing. If Magriel comes his way, putting out his wallet, saying „pass“, i would hesitate to say „take a seat“. So it is definately a double. But is it a take? Woolsey reverse says if there is any doubt, that it is a double, then it is a take. Hitting a possible shot isn't a superstrong threat, but what else? Getting some play against the stragglers is a parlay, a lot of equity is generated by the anchor.

Double, borderline take/pass.

With already 4 checkers behind White's anchor, it will be hard to gammon him, so I would double now because Black's structure is way better. As White, despite somewhat low gammon risk, I'd be hesitating. No structure whatsoever, but the game is so young at the same time. I think I would still take. Too lazy and no time to use a MET right now, so I'm going by gut feeling.

Double / Take

Something went wrong in this game. The cube should have been turned early on in this blitz by Black. Is it too late to double now? Is Black too good? In a match, he might be.

Were Black to double, could White eke out a take? My inclination would be to pass! White cannot really counterattack here. If he tries to, sooner or later he will leave a blot that Black hits. After that, White may be on the fast track to a gammon loss. White’s best strategy to win is to avoid contact, and play behind Black after Black enters from the bar. White should then try to build up his board as Black comes around. After his board has some teeth, White might be able to hit a last-minute shot from the 3pt.

Knowing this, Black should maintain contact. He needn’t be concerned about scurrying his rear checkers to safety. If he leaves them in White’s path, he will likely get the exchange of hits that he desires. Of course, White might roll a joker doublet, and point on his head, but Black cannot be concerned about that. With proper play, White will soon be on the bar again. White’s well-time 3pt holding game will lose a small percentage of gammons, perhaps around 4%. If we guess that Black loses none (obviously optimistic), then White needs to win 27% of the time to justify a take. Here is the calculation for a cash game:

White’s Equity( Double/Pass ) = -1.0
White’s Equity( Double/Take ) = 2 * (-73% - 4% gammons + 27%) = -1.0

I don’t think White is anywhere close to 27% in this problem. Black should play on, and see whether he can shake loose any more blots. If things don’t go his way, he can probably cash later if he wants to. In some ways, this is the opposite of the situation where Black is concerned about losing his market. Here, the market is already lost, and since there is no danger of it be regained in the near future, Black should keep the cube until that circumstance arises.

My solution: No double (too good), Pass

For the Record
I am so often wrong that I like to post my record in these messages. It's kind of a truth-in-advertising thing. Grunch: I have been answering these problems without the use of a bot, and before checking the excellent solutions of others, since Problem 28. My record at this writing is 50%.

I don't play match, but for money I would say Double/Drop. WTF are you going to do? Try to perpetually hit and build at the same time? White can't even start a hitting war since if white gets hit, it may be hard for him to come back in, so a take can't be right.

I think the same would apply for match if it's so early like 0-0. Maybe it's a take if you were down 4-0 or something, but I don't do match games so I don't know the doubling strategies there.

too good to double/pass imo

Note: All ‘cash game’ problems assume the Jacoby Rule is in effect. That is, you can’t win a gammon unless the cube has been turned.

The cube in the diagramm is on 1, right? For a redouble, it might be right, but for an initial double, how could it work? Holding off the cube, since black has a take again? But then you win less then 1 point. You have to give the syringe now. Perhaps you can get a take.

This one got me, too. When I first began thinking about it, I thought it was a money game. But it's not. It's the first game of a seven-point match.

Hm b has a 5 point board, a big racing lead and w sits with 4 stones at the 22 point and is nearly in the starting position. The game is still young but only for white?! In a 7 match this would be too good to double for me, by far. Im sure i miss something. For money i would double/pass. (doublechecked this uberkuber :-))
Thanks to Mr. Robertie his problems and answers are great !

Wow. I was fooled by the cash game mantra. That isn't needful if it is a match.
We are not to good. Double, and then coin flip. May be a pass. But i would take it against Stick or Bill (in a tournament). Because of the cube leverage. A 4 cube could be juicy.

chance of gammon is kinda high but I'm just gonna change my answer to double/pass, it seems much safer.

I don't think that gammon threats for Black are that high.

No double/take

Black really isn't threatening to do anything here. His front position is all locked up, so he's basically in a scramble to get his 5 checkers around. It's actually going to be a while before black will be able to get everyone around, and in the meantime white is going to keep hitting blots and building up his board.

Hold off on the double until some point when white has a blot for you to shoot at. Hitting a blot will be the type of market-loser that you're looking for.

I see your point Aaron, but Black's ahead in the race and structure-wise. If it's a take, why not double now and hope for a mistake pass with the intimidating 5-pt board?

That board is a permanent asset. If White doesn't want to provoke contact, fine, we're ahead in the race. Otherwise, we'll benefit from a hit exchange as we are outboarding him 5 points to 1.

If you think you can trick your opponent into a drop, then go ahead and ship it. I'm not sure you'll actually get as many drops as you think.

If white had left an indirect shot at a blot, I would upgrade this to a double/take. I think that's the spot where you can get mistaken drops (assuming that it's actually a double/take).

Ive played out this position(that I now know I obviously cant play as black but whatever) several times and have not once won a gammon. So I vote double/take just cos I probably dont know what to do here.

Hi,

we've played it ten times now, manually, and so far white has won once and lost 9 times.

All of whites losses are in the form of a 3-anchor with or without extra checkers.

After ten games I estimate the black equity on 0,66, so double/pass.
One more white win would bring the equity to about 0,50, so taking into account the quiz factor, this might be a borderline take/pass.

My guess (above) was that the gammon win rate for Black will be around 4%. If that is right, you haven't yet played enough trials to factor that in to your calculations. Having said that, I'm reassured that you've got this in solid pass territory.

I still think this is too good, but I worry that I'm all alone on an island!

hehe nono, you are not alone. Even if blacks gammon chances are low, why should`nt we pick them up as long as white is no threat? too good to double / pass for me

I don't expect to have many drops, but even a few would be a bonus, because I don't see a lot of downside about doubling now. Except maybe a more efficient double, which leads to your next point...

Yeah, I thought about whether it would be a drop or a take if White had a blot somewhere. I think that if it's an indirect shot, it's a take, but if it's a direct shot, it's a drop (or a marginal take at best).

And with the indirect shot, it's probably a very efficient double.

Hi Mike,

I should have been a bit completer with my post.

We didn't rollout till the end but until there was a clear position, mostly a position which was a clear 3 point holding anchor.

For a pure 3-anchor i took an equity of 0,55, for every extra outfield crossover i added 0,05 (a 5% gammonchance). So for an extra checker on the anchor (3 crossovers), i added 0,15 (a 15% gammonchance).

So the gammons were included, they raised the average equity. And based on that average (in my case 0,66) I tend towards double pass.

Hi Bjornar,

I played black against my wife, and my main strategy was to move the backcheckers.
From the midpoint i played straight into the innerboard, or else if possible to points 11 and 10.
What was your problem playing it for black?

The difficult decisions were mostly on whites side. If there were no contructive doubles, 61 or delta-2 moves white avoided direct shots (as long as black's on 21 a move to 14 is allright. And later on white started to make point 5 and 4. White rather dumped a checker on a low point than leaving a direct shot, not because being hit loses too much equity, but because staying on the bar would mean that white can't build up a board.

A few times white had to leave a direct shot, which she sometimes left before a stripped midpoint, and sometimes she hit a checker on the 24-point.

greetings k.