Problem of the Week #137: February 12


Money game, center cube, Black on roll.




Black to play 5-5.



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.

Race: Black 114, White 112

After the roll, Black will be leading 112-94 with White on roll, so about a 14-pip lead. I don't see the interest of playing 13/8 (2) 16/6 and stay behind, risking jokers such as 3-3 and 4-4. Maybe there's something I'm missing, but I like 20/5 16/11, preparing for a good bearoff with a 3rd checker on the 5-pt and leaving 15 shots. Of course, 20/10 16/6 would leave one less shot (14) and give one more return shots (5 vs 4), but I still prefer 20/5 16/11 because of the better bearoff structure.

20/5 16/11

Pre-flop, no one has raised. White is on TMP. That gives black the chance, to make an aggressive move, to see a nice flop, perhaps with a nice raise on the river or even playing for the gammon in an unraised pot.

16/1 6/1.

Every 4 and above will give White a problem. We can handle everything but a six. Let's just sitting tight, waiting for white doing the job for us.

20/10, 16/6...fewest shots, no trailer for me

16/1, 6/1

It seems like white has a lot of problematic rolls on his turn. There aren't that many rolls that white has that doesn't leave a shot open or destroy his home board structure. Since the cube hasn't been turned yet, we can risk something like 33 for this turn and turn the cube if white is forced to leave a blot.

The solution to the problems of this week is to One Touch Clean and Ban obvious troll posters, not to just lock threads and leave accounts active.

And 16/1 6/1.

I can say for sure that White leads in the pip count, 112 to 114, before this turn. That means Black will be up by 18 pips after this move. Other than that, I’m pretty much clueless!

Two opposing strategies are possible: Thematically, Black should try to look for ways to disengage. As the race leader, he should want to race. If he runs his back checkers 10 pips apiece, 20/10 16/6, only one blot will be exposed. He won’t like it if he is hit, but the real problem is that he won’t like it even when he is missed.

As things stand, White’s position is very brittle. One of his points will be broken on his next toss, and a blot may shake loose. But when Black runs, he solves White’s problem. By running, Black releases control of White’s outer board, and White will then slot builders for his 5pt.

The alternative strategy is a hybrid of running and holding. Black can play 16/6 13/8(2), leaving a blot behind on the 20pt. When White moves, he may hit Black, but that possibility was already on the table. When he is missed Black can either run, or play for a shot. In case he decides to stay back, he will have a 6 he can play from the 8pt, and plenty of spares inside.

Other ways to accomplish the same thing seem weaker. Making the 8pt and 1pt, for instance, leaves two blots outside. Making the 1pt and bringing the checker on the 16pt home leaves a brittle position. Using two of these 5s to clear the midpoint is a priority for me.

My solution: 16/6 13/8(2)

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 54%.

Problem 137:

White's position is stripped and after this move black leads the race with 94 - 112.

The best race move is (from the back) 20/5 16/11, risk all 4's = 14/36

The best move vs. the strippedness is 16/1 6/1, risk: (31,32,D3,D4,D1) = 7/36,
also there is some blitz-risk after (43,53,63,62), but they are 2/3 effective = 5,3/36
Total risk = 12,3/36.

So it seems to me that the less risky move here wins more gammons because of the lack of the white playability.

My answer 16/1 6/1

I missed the variation 20/10 16/6, it is less risky (13/36), but I still prefer my aforementioned answer

After reading the other posts, I have some remarks:

uberkuber: The better bear-off structure may count for 1pip less wastage.
It might differ about 1% in the race chance, that is far less than the 2,75% extra chance of being hit.

Taper_Mike: Although creative, your hybrid variation has one problem.
It makes the checkers on the midpoint only indirectly vulnerable, so it gives white 24 pips of playability.

Yeah, good point. Probably FPS from my part!

Well, I warned you that I was clueless!

Here is something I do know. When the group mind on this site chooses a play different from mine, my chance of being right falls dramatically. I can see merit in 16/1 6/1. As with my solution, Black can run on the next turn any time he has an awkward throw. If he does, the midpoint will give him valuable support in any exchange of hits.

That said, I have also learned that a single outside point and a straggler do always work well in tandem. In practice, both are often on the their own when it comes to making it home safely. On this roll, half of that can be accomplished now. That should be worth something (in exchange for the admittedly reduced control of the outfield). The fact that White’s midpoint is only indirectly vulnerable works both ways. Black is not shooting a direct at White, but neither is White aiming at Black.

Now I am worse than clueless, for I am also likely wrong!

My gut was 20/5, 16/11. However after re-examination, this moves puts you on the defensive and gives white the edge. Even though hes behind in the race, he has a direct shot, and even if he misses the 4 shot, with that roll he can clear his midpoint safely and have all the time in the world waiting for another shot when white has to clear HIS midpoint.

16/1, 6/1 puts white on the defensive as he trembles with each roll from here on out, instead of licking his chops with20/5, 16/11

End of first paragraph should say black not white srry