Study Position 01/21/12 Rollout & some alternate positions

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Study Position 01/21/12 Rollout & some alternate positions

Posted By: Jason Lee
Date: Sunday, 22 January 2012, at 4:00 p.m.

In Response To: Study Position 01/21/12 (Jason Lee)

Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?
Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

First, I'll note that in the actual position, I did not consider a cube, which now appears to be a pretty clear violation of "Every Roll is a Cube Decision."
Why didn't I cube? Since I didn't stop and think, "Is this a cube? No, because of X, Y, and Z," I can't really say I have an X, Y, and Z. But I can give SOME idea, since to my eye, it still looks pretty short.
What are some indications to cube?

The obvious: a five-prime in front of an anchor with three checkers. Now that I know XG thinks this is a strong double, I have little doubt that this is the key feature of the position.
No checkers out of play. White has two deep checkers, while not out of play, are no good for priming. So White cannot counterprime.
Equal board with better points.
A good anchor to prevent White from blitzing to equalize.
A White blot in the outfield that Blue could pick up along the way, which would probably be good.
No bad numbers. There aren't any rolls that immediately force us to bust up my prime.
7 hitting numbers (16, 36, 56, 33).
Behind in the match.

What are some bad things for Blue?

On the bar! and Four checkers back! These are surely the things that caused me to hold back on the cube.
Behind in the race.

What I want to do now is to alter the position, run them through XG and see if I can figure out the relative importance of the features. For expedience, I'll be doing just XGR++ for the alternate positions.

First I want to test what three checkers back does. I moved one of White's checkers to the 18 point, a pretty good spot for it. Clear no double.
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 1

White is Player 2

score: 1
pip: 126

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-B----ab--ccBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 62.21% (G:15.70% B:0.63%) 62.36% (G:15.77% B:0.63%)
Opponent Winning Chances: 37.79% (G:10.28% B:0.29%) 37.64% (G:10.50% B:0.30%)
Cubeless Equities +0.295 +0.602
Cubeful Equities
No double: +0.494
Double/Take: +0.407 (-0.088)
Double/Pass: +1.000 (+0.506)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 12.9%

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

If I stick that checker in an awkward spot, it's borderline.
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 2

White is Player 2

score: 1
pip: 121

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-B----ab--bcBbAc-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 66.13% (G:17.66% B:0.75%) 66.26% (G:17.50% B:0.74%)
Opponent Winning Chances: 33.87% (G:10.12% B:0.24%) 33.74% (G:10.07% B:0.23%)
Cubeless Equities +0.398 +0.820
Cubeful Equities
No double: +0.648 (-0.007)
Double/Take: +0.655
Double/Pass: +1.000 (+0.345)

Best Cube action: Double / Take

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Let's try putting that third rear checker somewhere in the outfield, say on the 10 point.
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 3

White is Player 2

score: 1
pip: 134

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-Ba---ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 60.75% (G:16.82% B:0.74%) 60.73% (G:16.91% B:0.74%)
Opponent Winning Chances: 39.25% (G:10.52% B:0.35%) 39.27% (G:10.72% B:0.37%)
Cubeless Equities +0.276 +0.556
Cubeful Equities
No double: +0.446
Double/Take: +0.351 (-0.096)
Double/Pass: +1.000 (+0.554)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 12.8%

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Maybe the 11 point?
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 4

White is Player 2

score: 1
pip: 133

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-B-a--ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 61.62% (G:16.70% B:0.71%) 61.81% (G:16.46% B:0.67%)
Opponent Winning Chances: 38.38% (G:10.11% B:0.32%) 38.19% (G:10.28% B:0.32%)
Cubeless Equities +0.297 +0.601
Cubeful Equities
No double: +0.477
Double/Take: +0.400 (-0.077)
Double/Pass: +1.000 (+0.523)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 11.4%

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Nothing is really changing much. That third checker back is important.

This time, let's put that checker on the 16 point, so that we have some extra hitters off the bar.
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 5

White is Player 2

score: 1
pip: 128

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-B----aba-bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 63.91% (G:17.14% B:0.75%) 63.94% (G:17.11% B:0.75%)
Opponent Winning Chances: 36.09% (G:10.00% B:0.31%) 36.06% (G:10.08% B:0.31%)
Cubeless Equities +0.349 +0.712
Cubeful Equities
No double: +0.558
Double/Take: +0.525 (-0.033)
Double/Pass: +1.000 (+0.442)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 6.6%

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Maybe the 17 point?
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 6

White is Player 2

score: 1
pip: 127

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---bBBCB-B----ab-abcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 64.85% (G:17.47% B:0.71%) 64.86% (G:17.32% B:0.69%)
Opponent Winning Chances: 35.15% (G:9.88% B:0.32%) 35.14% (G:9.67% B:0.31%)
Cubeless Equities +0.372 +0.763
Cubeful Equities
No double: +0.595
Double/Take: +0.580 (-0.015)
Double/Pass: +1.000 (+0.405)

Best Cube action: No double / Take
Percentage of wrong pass needed to make the double decision right: 3.4%

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

OK, that experiment is over. The third checker back is important to the position. Without it, we probably can't double.

Let's change the match score. If we make it -7/-7, it's still an easy double, a bit less so. We could keep adjusting this way, I'm sure eventually we'll find some score where we shouldn't double. This isn't a great exercise to discern features of the position.
Original Position

White is Player 2

score: 1
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:1:0:7:10
Blue on roll, cube action?

Analyzed in Rollout No double Double/Take
Player Winning Chances: 69.79% (G:19.72% B:0.79%) 69.98% (G:20.11% B:0.80%)
Opponent Winning Chances: 30.21% (G:7.63% B:0.22%) 30.02% (G:7.93% B:0.32%)
Cubeless Equities +0.522 +1.084
Cubeful Equities
No double: +0.836 (-0.096) ą0.011 (+0.825..+0.847)
Double/Take: +0.932 ą0.014 (+0.918..+0.946)
Double/Pass: +1.000 (+0.068)

Best Cube action: Double / Take
Rollout details
1296 Games rolled with Variance Reduction.
Dice Seed: 54713994
Moves and cube decisions: 4-ply

Double Decision confidence: 100.0%
Take Decision confidence: 100.0%
Duration: 1 hour 05 minutes

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Alternate Position 7

White is Player 2

score: 0
pip: 141

7 point match

pip: 155
score: 0

Blue is Player 1

XGID=---cBBCB-B----ab--bcBbAb-A:0:0:1:00:0:0:0:7:10
Blue on roll, cube action?

Analyzed in XG Roller++ No double Double/Take
Player Winning Chances: 69.32% (G:18.96% B:0.74%) 69.52% (G:18.95% B:0.75%)
Opponent Winning Chances: 30.68% (G:7.32% B:0.22%) 30.48% (G:7.33% B:0.22%)
Cubeless Equities +0.511 +1.052
Cubeful Equities
No double: +0.767 (-0.062)
Double/Take: +0.829
Double/Pass: +1.000 (+0.171)

Best Cube action: Double / Take

eXtreme Gammon Version: 2.01, MET: Kazaross XG2

Conclusion: *The* feature of this position which I clearly failed to grasp in the outset was the strength of having a broken 5-prime in front of 3 checkers.
JLee

Messages In This Thread

Study Position 01/21/12
Jason Lee -- Saturday, 21 January 2012, at 3:04 p.m.
- Study Position 01/21/12 Rollout & some alternate positions
  Jason Lee -- Sunday, 22 January 2012, at 4:00 p.m.
  - Study Position 01/21/12 Rollout & some alternate positions
    Casper van der Tak -- Sunday, 22 January 2012, at 5:16 p.m.
  - Study Position 01/21/12 Rollout & some alternate positions
    Daniel Murphy -- Sunday, 22 January 2012, at 6:05 p.m.
  - Bravo!
    Timothy Chow -- Sunday, 22 January 2012, at 8:35 p.m.
    - +1 ! *NM*
      Klaus Evers -- Sunday, 22 January 2012, at 10:08 p.m.

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