Discussion:
5pt or hit?
(too old to reply)
Timothy Chow
2024-01-29 14:11:21 UTC
Permalink
XGID=-b----DAC---cCa--b-dbAa-BA:1:1:1:11:0:0:0:0:10

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 X O X |
| X O | | O O X |
| X | | O |
| | | O |
| | X | |
| |BAR| |
| | | |
| | | X |
| O X | | X | +---+
| O X | | X O | | 2 |
| O X X | | X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 188 O: 151 X-O: 0-0
Cube: 2, X own cube
X to play 11

---
Tim Chow
Timothy Chow
2024-02-03 23:10:10 UTC
Permalink
XGID=-b----DAC---cCa--b-dbAa-BA:1:1:1:11:0:0:0:0:10

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 X O X |
| X O | | O O X |
| X | | O |
| | | O |
| | X | |
| |BAR| |
| | | |
| | | X |
| O X | | X | +---+
| O X | | X O | | 2 |
| O X X | | X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 188 O: 151 X-O: 0-0
Cube: 2, X own cube
X to play 11

Bar/24 is forced and 8/7 is obvious; the question is whether to hit
with 24/22* or make the 5pt with 6/5(2). This type of decision can
go either way, and has to be judged on a case-by-case basis. Here,
X is well behind in the pip count and wants to prime O, and 6/5(2)
does a great job of that. XG says the decision is not close. I have
given two variants below in which XG says the decision is closer,
though even in these variants, XG still favors 6/5(2).

1. Rollout¹ Bar/24 8/7 6/5(2) eq:+0.129
Player: 50.76% (G:13.82% B:0.79%)
Opponent: 49.24% (G:22.68% B:2.67%)
Confidence: ±0.015 (+0.115..+0.144) - [100.0%]

2. Rollout¹ Bar/22* 8/7 eq:+0.032 (-0.098)
Player: 46.12% (G:12.10% B:0.74%)
Opponent: 53.88% (G:19.29% B:1.40%)
Confidence: ±0.014 (+0.017..+0.046) - [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=-b----DAC---cC--ab-ccAa-BA:1:1:1:11:0:0:0:0:10

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 X O X |
| X O | | O O X |
| X | | O O |
| | | |
| | X | |
| |BAR| |
| | | |
| | | X |
| O X | | X | +---+
| O X | | X O | | 2 |
| O X X | | X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 188 O: 148 X-O: 0-0
Cube: 2, X own cube
X to play 11

1. Rollout¹ Bar/24 8/7 6/5(2) eq:+0.030
Player: 48.23% (G:12.81% B:0.81%)
Opponent: 51.77% (G:24.90% B:3.48%)
Confidence: ±0.016 (+0.015..+0.046) - [99.1%]

2. Rollout¹ Bar/22* 8/7 eq:+0.006 (-0.024)
Player: 45.58% (G:12.21% B:0.75%)
Opponent: 54.42% (G:20.58% B:1.71%)
Confidence: ±0.012 (-0.006..+0.018) - [0.9%]

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 2
---------

XGID=-a-a--DAC---cCa--b-dbAa-BA:1:1:1:11:0:0:0:0:10

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 X O X |
| X O | | O O X |
| X | | O |
| | | O |
| | X | |
| |BAR| |
| | | |
| | | X |
| O X | | X | +---+
| O X | | X | | 2 |
| O X X | | X O O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 188 O: 149 X-O: 0-0
Cube: 2, X own cube
X to play 11

1. Rollout¹ Bar/24 8/7 6/5(2) eq:-0.004
Player: 46.97% (G:11.85% B:0.71%)
Opponent: 53.03% (G:24.36% B:3.03%)
Confidence: ±0.014 (-0.019..+0.010) - [99.9%]

2. Rollout¹ Bar/22* 8/7 eq:-0.034 (-0.029)
Player: 44.06% (G:10.84% B:0.56%)
Opponent: 55.94% (G:19.60% B:1.46%)
Confidence: ±0.012 (-0.046..-0.022) - [0.1%]

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

---
Tim Chow

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