bearing in leading post-crawford

Walt

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May 21, 2012, 8:10:41 AM5/21/12

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XGID=abBBCBDB---------b-dbb-b--:1:1:1:62:4:1:0:5:10

X:Player 1 O:Player 2
Score is X:4 O:1 5 pt.(s) match.
+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O |
| O | | O O O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | X |
| | | X X | +---+
| X | | X X X X X O | | 2 |
| X | | X X X X X O | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 70 O: 135 X-O: 4-1/5
Cube: 2, X own cube
X to play 62

A simple play. What's your choice and why?

//Walt

Bradley K. Sherman

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May 21, 2012, 9:19:54 AM5/21/12

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Walt <walt_...@yahoo.com> wrote:
>Score is X:4 O:1 5 pt.(s) match.
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | O | | O O O O |
> | O | | O O O O |
> | | | O |
> | | | O |
> | | | |
> | |BAR| |
> | | O | |
> | | | X |
> | | | X X | +---+
> | X | | X X X X X O | | 2 |
> | X | | X X X X X O | +---+
> +12-11-10--9--8--7-------6--5--4--3--2--1-+

>Pip count X: 70 O: 135, X to play 62

Even if O throws the 6-1 after X plays the feel-good
7/5, X still has strong winning chances, but I'll
play the quiet 4/2 because I want to take a
checker off before I get hit to eliminate all
chances of getting gammoned.

--bks

badgolferman

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May 21, 2012, 9:20:58 AM5/21/12

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I'd play 7/5 now. O must get 1-6 to hurt me. Getting one in now will
eliminate the possibility of a six on my next roll leaving a blot,
unless it's double sixes.

Tim Chow

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May 21, 2012, 11:25:47 AM5/21/12

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It's essentially gammon save so we are more cautious than usual about
getting gammoned. 7/5 obviously gives O a 61 to hit immediately. 6/4
or 4/2 is safe for this turn, but then X has to clear his 6pt. 65
blots immediately, and other 6's leave X with the same problem next
roll, only with fewer spares to play with, and perhaps O will have a
stronger board by then. I don't think that this approach is any safer
overall, especially since 7/5 puts a spare on a useful point.

7/5 for me.

---
Tim Chow

Walt

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May 22, 2012, 10:31:49 AM5/22/12

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On 5/21/2012 8:10 AM, Walt wrote:
> XGID=abBBCBDB---------b-dbb-b--:1:1:1:62:4:1:0:5:10
>
> X:Player 1 O:Player 2
> Score is X:4 O:1 5 pt.(s) match.
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | O | | O O O O |
> | O | | O O O O |
> | | | O |
> | | | O |
> | | | |
> | |BAR| |
> | | O | |
> | | | X |
> | | | X X | +---+
> | X | | X X X X X O | | 2 |
> | X | | X X X X X O | +---+
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 70 O: 135 X-O: 4-1/5
> Cube: 2, X own cube
> X to play 62

A fairly close one: the better distribution after 7/5 is not worth
leaving two shots, but 7/5 is better than prematurely burying a checker
on the deuce. Note that 7/5 wins slightly fewer games than 6/4, but
wins more gammons, making 7/5 correct at (some) match scores where
gammons matter. I've rolled out 5a-5a centered cube below.

The gammon losses are miniscule for both plays, so I don't think GG is a
factor here.

XGID=abBBCBDB---------b-dbb-b--:1:1:1:62:4:1:0:5:10

1. Rollout¹ 6/4 eq:+0.632
Player: 81.71% (G:45.48% B:15.71%)
Opponent: 18.29% (G:0.12% B:0.00%)
Confidence: ±0.004 (+0.628..+0.635) - [100.0%]
Duration: 4 minutes 43 seconds

2. Rollout¹ 7/5 eq:+0.608 (-0.024)
Player: 80.56% (G:46.71% B:16.78%)
Opponent: 19.44% (G:0.16% B:0.01%)
Confidence: ±0.004 (+0.604..+0.612) - [0.0%]
Duration: 3 minutes 49 seconds

3. Rollout¹ 4/2 eq:+0.581 (-0.050)
Player: 79.21% (G:43.14% B:13.98%)
Opponent: 20.79% (G:0.13% B:0.01%)
Confidence: ±0.004 (+0.578..+0.585) - [0.0%]
Duration: 3 minutes 45 seconds

4. 2-ply 5/3 eq:+0.356 (-0.276)
Player: 69.96% (G:25.11% B:1.99%)
Opponent: 30.04% (G:2.08% B:0.08%)

¹ 1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.03, MET: Kazaross XG2

///////////////5a-5a rollout///////////////////////////////////////

XGID=abBBCBDB---------b-dbb-b--:0:0:1:62:0:0:0:5:10

X:Player 1 O:Player 2

Score is X:0 O:0 5 pt.(s) match.

+13-14-15-16-17-18------19-20-21-22-23-24-+
| O | | O O O O |
| O | | O O O O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | O | |
| | | X |
| | | X X |

| X | | X X X X X O |
| X | | X X X X X O |

+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 70 O: 135 X-O: 0-0/5
Cube: 1
X to play 62

1. Rollout¹ 7/5 eq:+1.074
Player: 82.37% (G:40.47% B:3.83%)
Opponent: 17.63% (G:0.15% B:0.00%)
Confidence: ±0.008 (+1.066..+1.081) - [99.6%]
Duration: 10 minutes 16 seconds

2. Rollout¹ 6/4 eq:+1.058 (-0.015)
Player: 83.09% (G:38.37% B:3.51%)
Opponent: 16.91% (G:0.09% B:0.00%)
Confidence: ±0.008 (+1.050..+1.067) - [0.4%]
Duration: 9 minutes 49 seconds

¹ 1296 Games rolled with Variance Reduction.
Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.03, MET: Kazaross XG2