Note that both players have a checker on the roof.

XGID=aAa--a------------abcbbbAA:1:-1:-1:00:0:0:3:0:10

X:Player 2 O:Player 1
Score is X:0 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | X X O |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | O | |
| | | |
| | | X | +---+
| | | X X X X X | | 2 |
| X | | X X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 120 O: 50 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

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

On 10/27/2022 9:20 AM, ah...Clem wrote:

Note that both players have a checker on the roof.

XGID=aAa--a------------abcbbbAA:1:-1:-1:00:0:0:3:0:10

X:Player 2 O:Player 1
Score is X:0 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | X X O |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | O | |
| | | |
| | | X | +---+
| | | X X X X X | | 2 |
| X | | X X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 120 O: 50 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

My tendency is to pass such cubes, but I've been surprised before
at how much resilience the underdog has in such positions. O
could anchor, which would make X's job more difficult. Even if
X closes out two checkers, it's not game over for O. I'll say D/T.

---
Tim Chow

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

Here's a somewhat similar decision I was faced with recently.
Normally, when participating in threads started by others, I
post a rollout immediately, but Paul seems to be implicitly
requesting that I not do so, so I'll give people a chance to
respond to this one before posting my rollout.

XGID=-aBB-CCB--a-----A------aAA:1:1:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X | | O X |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | | |
| | | |
| | | X X | +---+
| X | | X X X X | | 2 |
| O X | | X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 122 O: 41 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

---
Tim Chow

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

The reference position I used here was: two closed out on the bar with
all other checkers off is about 1/3 GWC or 33%.

But O has a third checker to send back, OTOH, she's not closed out yet.
But since X will hit loose with impunity it seemed like most of the time
O winds up with two on the bar with a minority of games with either
three on the bar or O makes her ace point.

And if it winds up with two on the bar with all other checkers off but
one, I don't know that reference position, but it seems like it's a few percentage less due to the additional roll to bear off.

Balancing all that together, I estimated several percent less GWC than
33%, enough to ship it but not enough to pass. The rollout puts it a
bit lower than my back of the envelope caluclation, but still D/T.

And in the multi-player online match (that is not a chouette) where this
came up X picked up the third checker and went on to win easily. XG was playing X.

XGID=aAa--a------------abcbbbAA:1:-1:-1:00:0:0:3:0:10
X:Player 2 O:Player 1

Score is X:0 O:0. Unlimited Game, Jacoby Beaver
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | X X O |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | O | |
| | | |
| | | X | +---+
| | | X X X X X | | 2 |
| X | | X X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 120 O: 50 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

Analyzed in Rollout
No redouble
Player Winning Chances: 76.51% (G:0.00% B:0.00%)
Opponent Winning Chances: 23.49% (G:1.28% B:0.39%)
Redouble/Take
Player Winning Chances: 76.86% (G:0.00% B:0.00%)
Opponent Winning Chances: 23.14% (G:1.22% B:0.33%)

Cubeless Equities: No Double=+0.514, Double=+1.043

Cubeful Equities:
No redouble: +0.856 (-0.060)
Redouble/Take: +0.917
Redouble/Pass: +1.000 (+0.083)

Best Cube action: Redouble / Take

Rollout:
1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.019 (+0.837..+0.876)
Confidence Double: ± 0.026 (+0.891..+0.942)

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

Duration: 1 minute 58 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)

This position is a good example of how XG's containment play
in such situations isn't very good. A rollout with stronger
settings (see below) declares this position to be a clear pass.

XGID=aaBBBCBA------------A--AaA:1:1:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | X X O |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | O | |
| | | |
| | | X | +---+
| | | X X X X X | | 2 |
| X | | X X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 120 O: 50 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

Analyzed in Rollout
No redouble
Player Winning Chances: 78.63% (G:0.00% B:0.00%)
Opponent Winning Chances: 21.37% (G:1.18% B:0.31%)
Redouble/Take
Player Winning Chances: 79.62% (G:0.00% B:0.00%)
Opponent Winning Chances: 20.38% (G:1.11% B:0.29%)

Cubeful Equities:
No redouble: +0.932 (-0.068)
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 and cube decisions: XG Roller+
Search interval: Large
Confidence No Double: ± 0.017 (+0.916..+0.949)
Confidence Double: ± 0.022 (+1.021..+1.066)

eXtreme Gammon Version: 2.19.211.pre-release

---
Tim Chow

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

On 10/30/2022 9:44 AM, Timothy Chow wrote:

Here's a somewhat similar decision I was faced with recently.
Normally, when participating in threads started by others, I
post a rollout immediately, but Paul seems to be implicitly
requesting that I not do so, so I'll give people a chance to
respond to this one before posting my rollout.

XGID=-aBB-CCB--a-----A------aAA:1:1:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
 +13-14-15-16-17-18------19-20-21-22-23-24-+
 |          X       |   |             O  X |
 |                  |   |                  |
 |                  |   |                  |
 |                  |   |                  |
 |                  | X |                  |
 |                  |BAR|                  |
 |                  |   |                  |
 |                  |   |                  |
 |                  |   | X  X             | +---+
 |                X |   | X  X     X  X    | | 2 |
 |       O        X |   | X  X     X  X  O | +---+
 +12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count  X: 122  O: 41 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

Looks fairly similar to the preceding problem. Most likely X will pick
up a second checker, but the closeout is not as likely. Also, O has a
chance to anchor on the four point giving her much more GWC.

With the previous position's rollout fresh in my mind I think it
technically a hold since O is in better shape here and the cube was not
that clear, but against a human I'd ship it since some will pass.

The abundant market losers (O'Hagan's law) would say ship it.

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

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

On 10/30/2022 4:47 PM, Timothy Chow wrote:

This position is a good example of how XG's containment play
in such situations isn't very good.  A rollout with stronger
settings (see below) declares this position to be a clear pass.

Darn. And I was so proud of myself for thinking like XG 3 ply.



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

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

On 10/30/2022 9:44 AM, I wrote:

Here's a somewhat similar decision I was faced with recently.
Normally, when participating in threads started by others, I
post a rollout immediately, but Paul seems to be implicitly
requesting that I not do so, so I'll give people a chance to
respond to this one before posting my rollout.

One reason I post rollouts immediately in such situations is
that because it's out of my usual routine, I tend to forget to
post the rollout if I don't do so immediately.

Anyway, the rollout is below. Like ah...clem, I thought that
O's position was better here than in ah...clem's position, but
according to the rollout, it's an even bigger pass.

XGID=-aBB-CCB--a-----A------aAA:1:1:1:00:0:0:0:0:10

Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X | | O X |
| | | |
| | | |
| | | |
| | X | |
| |BAR| |
| | | |
| | | |
| | | X X | +---+
| X | | X X X X | | 2 |
| O X | | X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 122 O: 41 X-O: 0-0
Cube: 2, X own cube
X on roll, cube action

Analyzed in Rollout
No redouble
Player Winning Chances: 79.07% (G:0.00% B:0.00%)
Opponent Winning Chances: 20.93% (G:2.84% B:0.92%)
Redouble/Take
Player Winning Chances: 81.74% (G:0.00% B:0.00%)
Opponent Winning Chances: 18.26% (G:2.60% B:0.77%)

Cubeful Equities:
No redouble: +0.964 (-0.036)
Redouble/Take: +1.106 (+0.106)
Redouble/Pass: +1.000

Best Cube action: Redouble / Pass

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves and cube decisions: XG Roller+
Search interval: Large
Confidence No Double: ± 0.016 (+0.948..+0.979)
Confidence Double: ± 0.025 (+1.081..+1.131)

eXtreme Gammon Version: 2.19.211.pre-release

---
Tim Chow

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

On Wednesday, November 9, 2022 at 3:04:29 AM UTC, Tim Chow wrote:

On 10/30/2022 9:44 AM, I wrote:

Here's a somewhat similar decision I was faced with recently.
Normally, when participating in threads started by others, I
post a rollout immediately, but Paul seems to be implicitly
requesting that I not do so, ...

Actually no, I didn't mean this, but I understand your interpretation.
On this forum, I get many more problems than I want to do so,
if I miss a solving opportunity because a position has been rolled out,
this is no loss to me whatsoever.

I think I know the thread that you mean. My thinking was something like this: Very often, when I come across a play that interests me, in a game against XG, I immediately post the rollout. I think it's just a lack of effort on my part ---
simply posting the rollout is easier. But when I've done this I've nearly always
thought something like: "Aren't I lazy! Tim would never do this. When Tim sees
interesting positions, he always poses them as a quiz (unless he's variantizing in a thread about a problem he's already posed)."

So I was surprised to see you post a rollout immediately with no solving opportunity.
But I didn't make a request about this in any way. In fact, my surprise was (very mildly)
positive because I felt less alone in the way I'd been posting.

Paul

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

On 11/9/2022 4:17 PM, peps...@gmail.com wrote:

So I was surprised to see you post a rollout immediately with no solving opportunity.
But I didn't make a request about this in any way. In fact, my surprise was (very mildly)
positive because I felt less alone in the way I'd been posting.

Ah, thanks for clarifying. That's good because it will make my
life easier going forward.

---
Tim Chow

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