XGID=-ba-BaC-D--BdB---bAe---A--: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-+
| X O X | | O X |
| X O | | O |
| | | O |
| | | O |
| | | O |
| |BAR| |
| | | |
| O X | | |
| O X | | X |
| O X X | | X X O |
| O X X | | X O X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 189 X-O: 0-0
Cube: 1
X on roll, cube action

---
Tim Chow

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

XGID=-ba-BaC-D--BdB---bAe---A--: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-+
| X O X | | O X |
| X O | | O |
| | | O |
| | | O |
| | | O |
| |BAR| |
| | | |
| O X | | |
| O X | | X |
| O X X | | X X O |
| O X X | | X O X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 189 X-O: 0-0
Cube: 1
X on roll, cube action

This position looks pretty bad for O at first glance. She is more than
40 pips down, with no new points made, while X has eleven checkers in
the zone and has partially escaped his back checkers. It looks like O
will get blitzed, or stuck in an ace-point game or a poorly-timed
backgame. However, O is not on the bar right now, and X has only a
two-point board with not much of a prime either. While X has good
gammon chances, O also has reasonable winning chances and should win
about 1/3 of the time, according to the rollout below.

In the variant, O's chances of making an advanced anchor are lower,
and the rollout results reflect this.

Analyzed in Rollout
No double
Player Winning Chances: 65.81% (G:28.60% B:3.19%)
Opponent Winning Chances: 34.19% (G:6.39% B:0.27%)
Double/Take
Player Winning Chances: 65.31% (G:29.26% B:3.54%)
Opponent Winning Chances: 34.69% (G:6.65% B:0.34%)

Cubeful Equities:
No double: +0.775 (-0.077)
Double/Take: +0.852
Double/Pass: +1.000 (+0.148)

Best Cube action: Double / Take

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.016 (+0.759..+0.791)
Confidence Double: ± 0.024 (+0.828..+0.875)

eXtreme Gammon Version: 2.19.207.pre-release

-------
Variant
-------

XGID=-ca-B-C-D--BdB---bAe---A--: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-+
| X O X | | O X |
| X O | | O |
| | | O |
| | | O |
| | | O |
| |BAR| |
| | | |
| O X | | |
| O X | | X O |
| O X X | | X X O |
| O X X | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 193 X-O: 0-0
Cube: 1
X on roll, cube action

Analyzed in Rollout
No double
Player Winning Chances: 67.47% (G:30.21% B:3.53%)
Opponent Winning Chances: 32.53% (G:5.73% B:0.24%)
Double/Take
Player Winning Chances: 67.24% (G:30.50% B:3.75%)
Opponent Winning Chances: 32.76% (G:5.79% B:0.25%)

Cubeful Equities:
No double: +0.899 (-0.089)
Double/Take: +0.988
Double/Pass: +1.000 (+0.012)

Best Cube action: Double / Take

Rollout:
2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.010 (+0.889..+0.909)
Confidence Double: ± 0.016 (+0.972..+1.005)

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

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

On Friday, March 11, 2022 at 7:42:42 PM UTC, Tim Chow wrote:

XGID=-ba-BaC-D--BdB---bAe---A--: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-+
| X O X | | O X |
| X O | | O |
| | | O |
| | | O |
| | | O |
| |BAR| |
| | | |
| O X | | |
| O X | | X |
| O X X | | X X O |
| O X X | | X O X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 189 X-O: 0-0
Cube: 1
X on roll, cube action
This position looks pretty bad for O at first glance. She is more than
40 pips down, with no new points made, while X has eleven checkers in
the zone and has partially escaped his back checkers. It looks like O
will get blitzed, or stuck in an ace-point game or a poorly-timed
backgame. However, O is not on the bar right now, and X has only a
two-point board with not much of a prime either. While X has good
gammon chances, O also has reasonable winning chances and should win
about 1/3 of the time, according to the rollout below.

In the variant, O's chances of making an advanced anchor are lower,
and the rollout results reflect this.

Analyzed in Rollout
No double
Player Winning Chances: 65.81% (G:28.60% B:3.19%)
Opponent Winning Chances: 34.19% (G:6.39% B:0.27%)
Double/Take
Player Winning Chances: 65.31% (G:29.26% B:3.54%)
Opponent Winning Chances: 34.69% (G:6.65% B:0.34%)

Cubeful Equities:
No double: +0.775 (-0.077)
Double/Take: +0.852
Double/Pass: +1.000 (+0.148)

Best Cube action: Double / Take

Rollout:
1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.016 (+0.759..+0.791)
Confidence Double: ± 0.024 (+0.828..+0.875)

eXtreme Gammon Version: 2.19.207.pre-release

-------
Variant
-------

XGID=-ca-B-C-D--BdB---bAe---A--: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-+
| X O X | | O X |
| X O | | O |
| | | O |
| | | O |
| | | O |
| |BAR| |
| | | |
| O X | | |
| O X | | X O |
| O X X | | X X O |
| O X X | | X X O O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 193 X-O: 0-0
Cube: 1
X on roll, cube action
Analyzed in Rollout
No double
Player Winning Chances: 67.47% (G:30.21% B:3.53%)
Opponent Winning Chances: 32.53% (G:5.73% B:0.24%)
Double/Take
Player Winning Chances: 67.24% (G:30.50% B:3.75%)
Opponent Winning Chances: 32.76% (G:5.79% B:0.25%)

Cubeful Equities:
No double: +0.899 (-0.089)
Double/Take: +0.988
Double/Pass: +1.000 (+0.012)

Best Cube action: Double / Take

Rollout:
2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
Confidence No Double: ± 0.010 (+0.889..+0.909)
Confidence Double: ± 0.016 (+0.972..+1.005)

eXtreme Gammon Version: 2.19.207.pre-release

--- > Tim Chow

Thanks for these positions. Your commentary on the original position
seems to have the flavour "It might look like a pass but it's actually an easy take."
(although you didn't exactly say this).
My perception was completely different. I saw it (correctly) as a very easy take,
but I wasn't at all sure whether it was a hold or a double. I suspect that I would have got
this right. But also, I would have estimated the favourite's equity at much less than 0.85
so I don't really understand this (type of) position.
On the other hand, the variant looks, from my intuitive quick assessment, to be terrible
for the underdog and I definitely would see the variant as a pass. The rollout doesn't
really make passing look particularly bad, but it may be suboptimal.
For me, the prospects for the underdog making an advanced anchor loom uppermost in my mind as I think about these positions so I would expect the change from this
ilustrated variantization to be quite large.

I spoke earlier about my terrible PR for blitz-cube positions. The reason seems to be that
I look at the underdog's blot on the 5 point and think "Good asset. The underdog is ready to
consolidate with an advanced anchor." whereas XG thinks "Horrible weakness. Big pass,
The favourite is set to attack this blot and win tons of gammons."

Paul

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

On 3/12/2022 6:24 AM, [email protected] wrote:

I look at the underdog's blot on the 5 point and think "Good asset. The underdog is ready to
consolidate with an advanced anchor." whereas XG thinks "Horrible weakness. Big pass,
The favourite is set to attack this blot and win tons of gammons."

Well, a blot on the 5pt can be both of these things, depending
on the position. In this particular position, where O is not on
the bar and has an anchor on X's 1pt, the blot on the 5pt is, on
balance, useful for O. But for example, in the standard reference
positions below, O is better off with a blot on the 2pt and than
on the 5pt.

XGID=aB-B-aC-A---dE---d-e----B-:0:0:1:00:0:0:3:0:10

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-+
| X O | | O X |
| X O | | O X |
| X O | | O |
| X O | | O |
| X | | O |
| |BAR| |
| | O | |
| O | | |
| O | | X |
| O | | X X X |
| O X | | X O X X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 159 X-O: 0-0
Cube: 1
X on roll, cube action

Analyzed in XG Roller++
Player Winning Chances: 61.45% (G:30.85% B:0.53%)
Opponent Winning Chances: 38.55% (G:9.00% B:0.45%)

Cubeless Equities: No Double=+0.448, Double=+0.901

Cubeful Equities:
No double: +0.600 (-0.023)
Double/Take: +0.623
Double/Pass: +1.000 (+0.377)

Best Cube action: Double / Take

-------------------------------------------------------

XGID=aBaB--C-A---dE---d-e----B-:0:0:1:00:0:0:3:0:10

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-+
| X O | | O X |
| X O | | O X |
| X O | | O |
| X O | | O |
| X | | O |
| |BAR| |
| | O | |
| O | | |
| O | | X |
| O | | X X X |
| O X | | X X O X |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 147 O: 162 X-O: 0-0
Cube: 1
X on roll, cube action

Analyzed in XG Roller++
Player Winning Chances: 60.06% (G:28.61% B:0.55%)
Opponent Winning Chances: 39.94% (G:9.79% B:0.46%)

Cubeless Equities: No Double=+0.390, Double=+0.787

Cubeful Equities:
No double: +0.541
Double/Take: +0.497 (-0.044)
Double/Pass: +1.000 (+0.459)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 8.0%

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

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