Although it's not really clear which player's position has "busted".


XGID=-ABBBBB--------A---b--gAB-:0:0:-1:00:0:0:0:0:10

X:Player 2 O:Player 1
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 |
| | | O O O O O |
| | | |
| | | |
| | | |
| |BAR| |
| | | 7 |
| | | X |
| | | X |
| | | X X O |
| O | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 33 O: 127 X-O: 0-0
Cube: 1
X on roll, cube action

Bonus question: Would Jacoby make a difference in the cube action?

--
Ah....Clem
The future is fun, the future is fair.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 8/20/2022 10:40 AM, ah....Clem wrote:

Although it's not really clear which player's position has "busted".

Neither, I would say.

XGID=-ABBBBB--------A---b--gAB-:0:0:-1:00:0:0:0:0:10

X:Player 2   O:Player 1
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 |
 |                  |   | O  O  O  O  O    |
 |                  |   |                  |
 |                  |   |                  |
 |                  |   |                  |
 |                  |BAR|                  |
 |                  |   |          7       |
 |                  |   |          X       |
 |                  |   |          X       |
 |                  |   | X        X     O |
 |       O          |   | X        X  O  O |
 +12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count  X: 33  O: 127 X-O: 0-0
Cube: 1
X on roll, cube action

O has plenty of chances to get and hit a shot, after which she has at
least an equal position. I would take this one. I'm not sure about
the double. Any doublets except 55 lose market, but that by itself
isn't enough. If X leaves a blot or two and O misses, does that lose
X's market? Not sure. I guess I would double but without too much
confidence.

Bonus question: Would Jacoby make a difference in the cube action?

I'd be more confident about doubling with Jacoby since there are some
sequences that leave X TG.

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

I really miffed this one, playing as O. I think I correctly saw 26
rolls that leave a blot for X, but underestimated my chance to hit by
simply multiplying 26/36 times 20/36 to get about a 40% chance of
hitting a shot. It's much more than that since a) sometimes X leaves
two blots and b) O has more than one chance to hit since X may still
blot next roll.

The other bad assumption is that X loses a gammon almost all the time
when he doesn't hit a shot for something like 50% gammmon losses. Since
the 40% number above is too low, this is too high. Plus, there are some scenarios where X winds up with two on the roof (which happened, since
this is kind of a chouettte)

Anyway, I came up with ~25% wins and ~50% gammon losses to arrive at
pass. This way underestimated GWC and way overestimated gammmon losses.

Bottom line is that X is only slightly favored but wins a lot of
gammons, putting this squarely in the D/T range.

Jacoby doesn't change anything, other than increasing the magnitude of
the blunder if X holds.



XGID=-ABBBBB--------A---b--gAB-:0:0:-1:00:0:0:0:0:10

X:Player 2 O:Player 1
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 |
| | | O O O O O |
| | | |
| | | |
| | | |
| |BAR| |
| | | 7 |
| | | X |
| | | X |
| | | X X O |
| O | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 33 O: 127 X-O: 0-0
Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 55.24% (G:34.14% B:8.36%)
Opponent Winning Chances: 44.76% (G:0.00% B:0.00%)
Double/Take
Player Winning Chances: 55.12% (G:33.59% B:8.81%)
Opponent Winning Chances: 44.88% (G:0.00% B:0.00%)

Cubeless Equities: No Double=+0.530, Double=+1.053

Cubeful Equities:
No double: +0.426 (-0.213)
Double/Take: +0.638
Double/Pass: +1.000 (+0.362)

Best Cube action: Double / Take

Rollout:
1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.015 (+0.411..+0.440)
Confidence Double: ± 0.024 (+0.615..+0.662)

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%

Duration: 2 minutes 46 seconds

eXtreme Gammon Version: 2.10

--
Ah....Clem
The future is fun, the future is fair.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, August 22, 2022 at 8:34:59 PM UTC+1, ah....Clem wrote:

I really miffed this one, playing as O. I think I correctly saw 26
rolls that leave a blot for X, but underestimated my chance to hit by
simply multiplying 26/36 times 20/36 to get about a 40% chance of
hitting a shot. It's much more than that since a) sometimes X leaves
two blots and b) O has more than one chance to hit since X may still
blot next roll.

The other bad assumption is that X loses a gammon almost all the time
when he doesn't hit a shot for something like 50% gammmon losses. Since
the 40% number above is too low, this is too high. Plus, there are some scenarios where X winds up with two on the roof (which happened, since
this is kind of a chouettte)

Anyway, I came up with ~25% wins and ~50% gammon losses to arrive at
pass. This way underestimated GWC and way overestimated gammmon losses.

Bottom line is that X is only slightly favored but wins a lot of
gammons, putting this squarely in the D/T range.

Jacoby doesn't change anything, other than increasing the magnitude of
the blunder if X holds.
XGID=-ABBBBB--------A---b--gAB-:0:0:-1:00:0:0:0:0:10

X:Player 2 O:Player 1
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 |
| | | O O O O O |
| | | |
| | | |
| | | |
| |BAR| |
| | | 7 |
| | | X |
| | | X |
| | | X X O |
| O | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 33 O: 127 X-O: 0-0
Cube: 1
X on roll, cube action
Analyzed in Rollout
No double
Player Winning Chances: 55.24% (G:34.14% B:8.36%)
Opponent Winning Chances: 44.76% (G:0.00% B:0.00%)
Double/Take
Player Winning Chances: 55.12% (G:33.59% B:8.81%)
Opponent Winning Chances: 44.88% (G:0.00% B:0.00%)

Cubeless Equities: No Double=+0.530, Double=+1.053

Cubeful Equities:
No double: +0.426 (-0.213)
Double/Take: +0.638
Double/Pass: +1.000 (+0.362)

Best Cube action: Double / Take

Rollout:
1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.015 (+0.411..+0.440)
Confidence Double: ± 0.024 (+0.615..+0.662)

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%

Duration: 2 minutes 46 seconds

eXtreme Gammon Version: 2.10
--
Ah....Clem
The future is fun, the future is fair.

If I can tie in this position with other threads:
I don't think your bad pass here is an argument for using the line of reasoning (in other positions) --
"If you don't know whether it's a double or not, double because the opponent may pass."

It isn't any stronger then the diametrically opposite practical position:
"If you don't know whether it's a double or not, then hold because, even if you lose your market, your
opponent may wrongly take."

Here, the double is theoretically correct, so we don't need to worry about such practical considerations.
I'm just making a more general point.

Paul

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sunday, August 21, 2022 at 6:03:24 AM UTC+1, Tim Chow wrote:

On 8/20/2022 10:40 AM, ah....Clem wrote:

Although it's not really clear which player's position has "busted".

Neither, I would say.

XGID=-ABBBBB--------A---b--gAB-:0:0:-1:00:0:0:0:0:10

X:Player 2 O:Player 1
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 |
| | | O O O O O |
| | | |
| | | |
| | | |
| |BAR| |
| | | 7 |
| | | X |
| | | X |
| | | X X O |
| O | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 33 O: 127 X-O: 0-0
Cube: 1
X on roll, cube action

O has plenty of chances to get and hit a shot, after which she has at
least an equal position. I would take this one. I'm not sure about
the double. Any doublets except 55 lose market, but that by itself
isn't enough. If X leaves a blot or two and O misses, does that lose
X's market? Not sure. I guess I would double but without too much
confidence.

Bonus question: Would Jacoby make a difference in the cube action?

I'd be more confident about doubling with Jacoby since there are some sequences that leave X TG.

My thinking would be on the same line as yours.
I could easily have wrongly held this one, particularly OTB, but holding's a big mistake here.

Paul

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 8/23/2022 12:05 PM, peps...@gmail.com wrote:

If I can tie in this position with other threads:
I don't think your bad pass here is an argument for using the line of reasoning (in other positions) --
"If you don't know whether it's a double or not, double because the opponent may pass."

The usual adage I've heard (Woolsey's law) is, "If you don't know
whether it's a *take* or not, then double." The justification isn't
just that the opponent may pass. See here for Woolsey's full article:

https://bkgm.com/articles/GOL/Aug02/rule.htm

---
Tim Chow

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wednesday, August 24, 2022 at 3:04:49 AM UTC+1, Tim Chow wrote:

On 8/23/2022 12:05 PM, peps...@gmail.com wrote:

If I can tie in this position with other threads:
I don't think your bad pass here is an argument for using the line of reasoning (in other positions) --
"If you don't know whether it's a double or not, double because the opponent may pass."

The usual adage I've heard (Woolsey's law) is, "If you don't know
whether it's a *take* or not, then double." The justification isn't
just that the opponent may pass. See here for Woolsey's full article:

https://bkgm.com/articles/GOL/Aug02/rule.htm

---
Tim Chow

Well, that makes sense, yes.
But Ah...Clem has said many many many times including in his incarnations as Walt that
he believes that if you don't know if it's a double, you should double because your opponent may pass.
I mean he's said this like about 30 times, I think.
Now, Robertie does sometimes also say things like "If you don't know whether it's a double, then double because
your opponent may pass."
But there's a massive difference between Robertie's context and Ah..Clem's context.
Ah...Clem just says this indiscriminatingly, whenever he's unsure of the double (or thinks it may be
a close decision). But Robertie _only_ makes this comment with regard to problems that look deceptively
stronger than they are and where a pass is practically likely _because of how the position seems_.

For example, suppose your racing lead puts you around the margin between ND/T and D/T.
No competent player would pass a racing cube like this in a standard racing position.
But Ah...Clem still says "Double because they may pass" even when the position looks nowhere near a pass.

Paul

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)