Discussion:
How to prime a single checker
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Timothy Chow
2024-03-22 02:45:40 UTC
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XGID=-a--BBBDBb--aB---c-bd-bA--:1:-1:1:43:0:0:0:0:10

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 | +---+
| X O | | O O O | | 2 |
| O | | O | +---+
| | | O |
| | | |
| |BAR| |
| | | |
| X | | |
| X | | |
| O X X | | X X X |
| O O X X | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 123 O: 131 X-O: 0-0
Cube: 2, O own cube
X to play 43

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Tim Chow
Timothy Chow
2024-03-25 12:30:49 UTC
Permalink
XGID=-a--BBBDBb--aB---c-bd-bA--:1:-1:1:43:0:0:0:0:10

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 | +---+
| X O | | O O O | | 2 |
| O | | O | +---+
| | | O |
| | | |
| |BAR| |
| | | |
| X | | |
| X | | |
| O X X | | X X X |
| O O X X | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 123 O: 131 X-O: 0-0
Cube: 2, O own cube
X to play 43

I tried slotting the front of my prime, but XG says that's too risky.
It's a more viable plan in the variant below, where O's 2's are duped.

1. Rollout¹ 8/5 8/4 eq:+0.110
Player: 58.07% (G:20.58% B:0.75%)
Opponent: 41.93% (G:11.04% B:0.32%)
Confidence: ±0.008 (+0.102..+0.119) - [100.0%]

2. Rollout¹ 7/4 7/3 eq:+0.025 (-0.085)
Player: 57.09% (G:20.19% B:1.00%)
Opponent: 42.91% (G:16.85% B:0.53%)
Confidence: ±0.010 (+0.015..+0.035) - [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
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XGID=-a--BBBDBb--aB---c-cbabA--:1:-1:1:43:0:0:0:0:10

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 X | +---+
| X O | | O O O | | 2 |
| O | | O | +---+
| | | |
| | | |
| |BAR| |
| | | |
| X | | |
| X | | |
| O X X | | X X X |
| O O X X | | X X X O |
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 123 O: 131 X-O: 0-0
Cube: 2, O own cube
X to play 43

1. Rollout¹ 8/5 8/4 eq:-0.054
Player: 53.01% (G:19.74% B:0.79%)
Opponent: 46.99% (G:13.86% B:0.48%)
Confidence: ±0.007 (-0.061..-0.047) - [98.7%]

2. Rollout¹ 7/4 7/3 eq:-0.065 (-0.012)
Player: 54.32% (G:20.03% B:0.90%)
Opponent: 45.68% (G:17.87% B:0.71%)
Confidence: ±0.007 (-0.073..-0.058) - [1.3%]

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

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Tim Chow

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