From
Timothy Chow@21:1/5 to
All on Sun Dec 31 09:26:44 2023
XGID=-a---BCBC----C-babccc---AA:0:0:1:33:0:0:0:0:10
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X |
| X O O O | | O O |
| X O | | O O |
| | | |
| | X | |
| |BAR| |
| | | |
| | | |
| X | | X |
| X X | | X X |
| X X | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 154 O: 123 X-O: 0-0
Cube: 1
X to play 33
Stepping up both checkers to the edge of a prime even when there is a significant risk of being pointed on is a common theme. But I often see
players eschewing it, reasoning that there's no point in stepping up if
we're just going to get pointed on. That kind of logic is often valid
if the opponent has a blitzing threat, but this is a priming position.
For example, suppose we step up with 24/21 and O rolls a 4. She is then
faced with a choice of pointing on her 4pt or her 3pt. Pointing on her
4pt comes at the cost of giving up her 8pt and giving X a considerable
number of return shots. Pointing on her 3pt is safer, but allows X to
anchor with a 4 and to hit back with some 5's. By contrast, if X stays
back and plays something like bar/22 13/10(2) 8/5, then O's 4's play
much better.
With a spare on O's 8pt (Variant 1) the rollout says that the decision
is much closer. Also see Variant 2, where X has the option of making
his 3pt.
1. Rollout¹ Bar/22 24/21 13/10(2) eq:-0.424
Player: 43.29% (G:8.40% B:0.44%)
Opponent: 56.71% (G:28.29% B:1.05%)
Confidence: ±0.012 (-0.436..-0.412) - [100.0%]
2. Rollout¹ Bar/22 13/10(2) 8/5 eq:-0.501 (-0.076)
Player: 40.33% (G:8.73% B:0.39%)
Opponent: 59.67% (G:24.37% B:1.16%)
Confidence: ±0.015 (-0.516..-0.485) - [0.0%]
3. Rollout¹ Bar/22 13/10(3) eq:-0.517 (-0.093)
Player: 40.14% (G:8.18% B:0.38%)
Opponent: 59.86% (G:24.13% B:1.01%)
Confidence: ±0.016 (-0.533..-0.501) - [0.0%]
¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.211.pre-release
---------
Variant 1
---------
XGID=-a---BCBC----C-bacccb---AA:0:0:1:33:0:0:0:0:10
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X |
| X O O O | | O O |
| X O O | | O |
| | | |
| | X | |
| |BAR| |
| | | |
| | | |
| X | | X |
| X X | | X X |
| X X | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 154 O: 126 X-O: 0-0
Cube: 1
X to play 33
1. Rollout¹ Bar/22 24/21 13/10(2) eq:-0.443
Player: 42.41% (G:8.86% B:0.45%)
Opponent: 57.59% (G:26.95% B:1.10%)
Confidence: ±0.010 (-0.453..-0.434) - [91.0%]
2. Rollout¹ Bar/22 13/10(2) 8/5 eq:-0.454 (-0.011)
Player: 40.53% (G:9.26% B:0.39%)
Opponent: 59.47% (G:21.85% B:1.07%)
Confidence: ±0.012 (-0.467..-0.442) - [9.0%]
3. Rollout² Bar/22 13/10(3) eq:-0.477 (-0.034)
Player: 40.01% (G:8.57% B:0.41%)
Opponent: 59.99% (G:21.03% B:0.87%)
Confidence: ±0.016 (-0.493..-0.461) - [0.0%]
¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
² 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.211.pre-release
---------
Variant 2
---------
XGID=-a---BCBCA---B-babccc---AA:0:0:1:33:0:0:0:0:10
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| X O O O O | | O O X |
| X O O O | | O O |
| O | | O O |
| | | |
| | X | |
| |BAR| |
| | | |
| | | |
| X | | X |
| X X | | X X |
| X X X | | X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 150 O: 123 X-O: 0-0
Cube: 1
X to play 33
1. Rollout¹ Bar/22 9/3 6/3 eq:-0.445
Player: 41.31% (G:9.00% B:0.45%)
Opponent: 58.69% (G:23.40% B:1.13%)
Confidence: ±0.011 (-0.456..-0.434) - [99.8%]
2. Rollout¹ Bar/22 24/21 13/10(2) eq:-0.466 (-0.021)
Player: 41.40% (G:8.44% B:0.42%)
Opponent: 58.60% (G:29.17% B:1.36%)
Confidence: ±0.009 (-0.475..-0.457) - [0.2%]
¹ 2592 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
eXtreme Gammon Version: 2.19.211.pre-release
---
Tim Chow
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)