XGID=b-BDBBBA-------abbbcbB-a--:0:0:1:00:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O O O | | O O X O |
| O O O | | O O X |
| | | O |
| | | |
| | | |
| |BAR| |
| | O | |
| | O | X |
| | | X |
| | | X X X X X |
| X | | X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 95 O: 138 X-O: 0-0
Cube: 1
X on roll, cube action
On Thursday, December 2, 2021 at 1:21:54 PM UTC, Tim Chow wrote:
XGID=b-BDBBBA-------abbbcbB-a--:0:0:1:00:0:0:0:0:10
X:Player 1 O:Player 2Time for a backgammon riddle.
Score is X:0 O:0. Unlimited Game +13-14-15-16-17-18------19-20-21-22-23-24-+
| O O O O | | O O X O |
| O O O | | O O X |
| | | O |
| | | |
| | | |
| |BAR| |
| | O | |
| | O | X |
| | | X |
| | | X X X X X |
| X | | X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 95 O: 138 X-O: 0-0
Cube: 1
X on roll, cube action
Why would an expert find your problem easy?
Because she would find the answer in a (Walter) trice.
I'm sure there's a similar position in Backgammon Boot Camp,
but I don't remember it exactly, and nor do I remember where my copy is.
The Trice position was a pass, but the author indicated it was somewhat close.
However, the on-roll player had more timing in the Trice book if I remember. And that would swing the position from a pass to a take.
D/T for me.
Paul
XGID=b-BDBBBA-------abbbcbB-a--:0:0:1:00:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O O O O | | O O X O |
| O O O | | O O X |
| | | O |
| | | |
| | | |
| |BAR| |
| | O | |
| | O | X |
| | | X |
| | | X X X X X |
| X | | X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 95 O: 138 X-O: 0-0
Cube: 1
X on roll, cube action
Well, if you've seen the rollout for the previous position, then
you know that this one has to be a double, and it's the take that's
in question. According to the rollout, it's a pass, though not by
a huge margin by prime-versus-prime-cube standards.
I'm not sure exactly what position from "Boot Camp" Paul has in
mind, but at the end of this post, I give my best guess.
Analyzed in Rollout
No double
Player Winning Chances: 63.53% (G:46.48% B:1.68%)
Opponent Winning Chances: 36.47% (G:6.70% B:0.23%)
Double/Take
Player Winning Chances: 63.66% (G:47.12% B:1.65%)
Opponent Winning Chances: 36.34% (G:6.85% B:0.25%)
Cubeful Equities:
No double: +0.749 (-0.251)
Double/Take: +1.044 (+0.044)
Double/Pass: +1.000
Best Cube action: Double / Pass
Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.013 (+0.737..+0.762)
Confidence Double: ± 0.022 (+1.022..+1.065)
eXtreme Gammon Version: 2.19.207.pre-release
-----------------------
Boot Camp Position 6-12
-----------------------
XGID=aBBBBCC-----------abcccbA-:0:0:1:00:0:0:0:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O O X |
| | | O O O O O |
| | | O O O |
| | | |
| | | |
| |BAR| |
| | O | |
| | | |
| | | X X |
| | | X X X X X X |
| | | X X X X X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 77 O: 84 X-O: 0-0
Cube: 1
X on roll, cube action
Analyzed in Rollout
No double
Player Winning Chances: 68.71% (G:25.39% B:0.59%)
Opponent Winning Chances: 31.29% (G:1.65% B:0.04%)
Double/Take
Player Winning Chances: 68.96% (G:25.07% B:0.55%)
Opponent Winning Chances: 31.04% (G:1.65% B:0.04%)
Cubeful Equities:
No double: +0.679 (-0.321)
Double/Take: +1.048 (+0.048)
Double/Pass: +1.000
Best Cube action: Double / Pass
Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.009 (+0.670..+0.689)
Confidence Double: ± 0.010 (+1.038..+1.058)
No, it can't be this guess because (part of) the justification for the pass is something like "If ... rolls 6, ... is almost certain to get a gammon".
That clearly doesn't apply here.
Do you have another guess?
On 12/4/2021 2:37 PM, peps...@gmail.com wrote:Hmmm. You might be right. Does it also say (something like) "Can .. take this? Not really." But it isn't at all clear on how big the pass is.
No, it can't be this guess because (part of) the justification for the pass is something like "If ... rolls 6, ... is almost certain to get a gammon".
That clearly doesn't apply here.
Do you have another guess?No. If you insist on this additional condition, then I don't see
anything in "Boot Camp" that looks like a good match.
What Trice does say about Position 6-12, which I posted, is this:
"A 6 on the first roll will give him about a 40% chance to win a
gammon." It still looks to me like the best match; possibly you
just misremembered "40%" as "almost certain."
---
Tim Chow
On Saturday, December 4, 2021 at 8:22:18 PM UTC, Tim Chow wrote:
What Trice does say about Position 6-12, which I posted, is this:Hmmm. You might be right. Does it also say (something like) "Can .. take this? Not really." But it isn't at all clear on how big the pass is.
"A 6 on the first roll will give him about a 40% chance to win a
gammon." It still looks to me like the best match; possibly you
just misremembered "40%" as "almost certain."
---
Tim Chow
On 12/4/2021 3:44 PM, peps...@gmail.com wrote:
On Saturday, December 4, 2021 at 8:22:18 PM UTC, Tim Chow wrote:Trice doesn't say that. He says, "Obviously, the take/drop question
What Trice does say about Position 6-12, which I posted, is this:Hmmm. You might be right. Does it also say (something like) "Can .. take this? Not really." But it isn't at all clear on how big the pass is.
"A 6 on the first roll will give him about a 40% chance to win a
gammon." It still looks to me like the best match; possibly you
just misremembered "40%" as "almost certain."
---
Tim Chow
is a tough one, with the answer depending on the actual gammon ratio
and the value of the cube. Rollouts indicate that it's a drop for
money." He gives rollout information indicating that it's a 1.019 pass.
It sounds to me that you're conflating a Trice position with one or
more positions from Robertie's "501" book. Not giving rollout info
and saying "Can ... take this? Not really" sounds a lot like 501.
Below is Problem 267 from 501. Among Robertie's comments are: "That's
a total of 16 games where Black hops the prime before his board breaks.
In almost all of these games, Black wins a gammon."
Note that Robertie says "Can White take? Not really" in the comments to
a totally unrelated position (Problem 382).
XGID=bBBBBBB-A-aa------bbbbcB--:1:1:1:00:0:0:3:0:10
X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O X |
| O | | O O O O X |
| | | O |
| | | |
| | | |
| |BAR| |
| | O | |
| | O | |
| | | | +---+
| | | X X X X X X | | 2 |
| O O X | | X X X X X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 96 O: 132 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action
Analyzed in Rollout
No redouble
Player Winning Chances: 61.17% (G:49.55% B:5.17%)
Opponent Winning Chances: 38.83% (G:8.96% B:0.31%)
Redouble/Take
Player Winning Chances: 61.52% (G:49.76% B:4.79%)
Opponent Winning Chances: 38.48% (G:8.83% B:0.30%)
Cubeful Equities:
No redouble: +0.762 (-0.238)
Redouble/Take: +1.043 (+0.043)
Redouble/Pass: +1.000
Best Cube action: Redouble / Pass
Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.008 (+0.753..+0.770)
Confidence Double: ± 0.017 (+1.026..+1.060)
eXtreme Gammon Version: 2.19.207.pre-release
On Sunday, December 5, 2021 at 2:11:49 AM UTC, Tim Chow wrote:[...]
Below is Problem 267 from 501. Among Robertie's comments are: "That's
a total of 16 games where Black hops the prime before his board breaks.
In almost all of these games, Black wins a gammon."
Note that Robertie says "Can White take? Not really" in the comments to
a totally unrelated position (Problem 382).
Great! We've finally resolved it. Robertie's 382 was my (inaccurately remembered) reference.
But I still see these positions (his position and yours) as very similar rather than "totally unrelated".
On 12/5/2021 5:43 AM, peps...@gmail.com wrote:
On Sunday, December 5, 2021 at 2:11:49 AM UTC, Tim Chow wrote:[...]
Below is Problem 267 from 501. Among Robertie's comments are: "That's
a total of 16 games where Black hops the prime before his board breaks.
In almost all of these games, Black wins a gammon."
Note that Robertie says "Can White take? Not really" in the comments to
a totally unrelated position (Problem 382).
Great! We've finally resolved it. Robertie's 382 was my (inaccurately remembered) reference.Problem 267 is very similar to my position.
But I still see these positions (his position and yours) as very similar rather than "totally unrelated".
Problem 382 is totally unrelated.
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