On Tuesday, November 23, 2021 at 4:45:45 PM UTC-5, Tim Chow wrote:
XGID=-a----E-C-AaeC---b-d-b--BA:0:0:1:55:0:0:0:0:10
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-+
| X O | | O O X |
| X O | | O O X |
| X | | O |
| | | O |
| | X | |
| |BAR| |
| O | | X |
| O | | X |
| O X | | X |
| O X | | X |
| O O X X | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 176 O: 151 X-O: 0-0
Cube: 1
X to play 55
In the previous "Early 55" problem, none of the respondents wanted to
play 6/1*(2), but that's what XG wants to do here. I did play 6/1*(2) OTB but for my last 5, I chose 20/15, which XG really dislikes; X wouldn't mind anchoring on O's 5pt, and running out gives O better return shots.
Anticipating that some people might go for bar/10 13/8, I tried to find a variant where XG thought it was a viable play.
1. Rollout¹ Bar/20 13/8 6/1*(2) eq:-0.341
Player: 40.68% (G:14.36% B:0.30%)
Opponent: 59.32% (G:16.97% B:1.25%)
Confidence: ±0.015 (-0.356..-0.327) - [100.0%]
2. Rollout¹ Bar/20 10/5 6/1*(2) eq:-0.410 (-0.069)
Player: 39.28% (G:12.97% B:0.32%)
Opponent: 60.72% (G:18.76% B:1.54%)
Confidence: ±0.015 (-0.425..-0.395) - [0.0%]
3. Rollout¹ Bar/15 6/1*(2) eq:-0.428 (-0.087)
Player: 38.85% (G:12.56% B:0.24%)
Opponent: 61.15% (G:18.02% B:1.25%)
Confidence: ±0.017 (-0.445..-0.412) - [0.0%]
4. Rollout¹ Bar/10 13/8 eq:-0.445 (-0.104)
Player: 39.25% (G:10.19% B:0.37%)
Opponent: 60.75% (G:17.33% B:1.01%)
Confidence: ±0.016 (-0.461..-0.429) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.207.pre-release
-------
Variant
-------
XGID=-a----E-C-AaeD---b-d-b--AA:0:0:1:55:0:0:0:0:10
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-+
| X O | | O O X |
| X O | | O O |
| X | | O |
| X | | O |
| | X | |
| |BAR| |
| O | | X |
| O | | X |
| O X | | X |
| O X | | X |
| O O X X | | X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 165 O: 151 X-O: 0-0
Cube: 1
X to play 55
1. Rollout¹ Bar/20 13/8 6/1*(2) eq:-0.073
Player: 47.06% (G:16.62% B:0.46%)
Opponent: 52.94% (G:13.72% B:0.68%)
Confidence: ±0.011 (-0.084..-0.063) - [97.7%]
2. Rollout¹ Bar/10 13/8 eq:-0.088 (-0.015)
Player: 48.39% (G:10.90% B:0.36%)
Opponent: 51.61% (G:13.46% B:0.44%)
Confidence: ±0.010 (-0.098..-0.079) - [2.3%]
¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.207.pre-release
---
Tim Chow
Assuming multiple checkers back it's virtually never correct to play 20/15 with the last ace unslotting the anchor in these types of positions.
Stick
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