A surprising fact about Max Urban's "5 plays" position

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A surprising fact about Max Urban's "5 plays" position

Posted By: Timothy Chow
Date: Tuesday, 11 May 2010, at 3:57 a.m.

Max Urban recently posted a position in which the top play of 13/3* beat out the two nearest competitors 11/1 and 13/7 11/7 by over 0.100 EMG. In an effort to understand this position I tried rolling it out for money. To my surprise the top three plays rolled out to be quite close for money. Can anyone explain why the original score (6a7a) should make such a difference? Does XG concur with these results?
Unlimited game: tchow to play 64

gnubg 128

tchow 148
Position ID: HHcXAESxHeQBMA Match ID: UQkTAAAACAAA

# Ply Move Equity

• 1 R 13/3* +0.498

0.587 0.257 0.012 - 0.413 0.164 0.018 +0.261 +0.498

0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.004

Full cubeful rollout with var.redn.

5184 games, Mersenne Twister dice gen. with seed 852390721 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

2 R 11/1 +0.484 ( -0.014)

0.561 0.240 0.009 - 0.439 0.129 0.007 +0.236 +0.484

0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.005

Full cubeful rollout with var.redn.

5184 games, Mersenne Twister dice gen. with seed 852390721 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

3 R 13/7 11/7 +0.476 ( -0.022)

0.569 0.216 0.009 - 0.431 0.139 0.008 +0.215 +0.476

0.001 0.001 0.000 - 0.001 0.001 0.000 0.002 0.005

Full cubeful rollout with var.redn.

5184 games, Mersenne Twister dice gen. with seed 852390721 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

I also rolled out the position with the cube on the other side:
Unlimited game: tchow to play 64

gnubg 128

tchow 148
Position ID: HHcXAESxHeQBMA Match ID: QQkTAAAACAAA

# Ply Move Equity

• 1 R 13/3* +0.162

0.600 0.269 0.012 - 0.400 0.161 0.018 +0.303 +0.162

0.002 0.002 0.001 - 0.002 0.002 0.001 0.005 0.010

Full cubeful rollout with var.redn.

1296 games, Mersenne Twister dice gen. with seed 851744694 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

2 R 11/1 +0.077 ( -0.086)

0.568 0.242 0.009 - 0.432 0.129 0.007 +0.251 +0.077

0.001 0.002 0.001 - 0.001 0.001 0.000 0.004 0.007

Full cubeful rollout with var.redn.

1296 games, Mersenne Twister dice gen. with seed 851744694 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]

3 R 13/7 11/7 +0.064 ( -0.098)

0.574 0.220 0.010 - 0.426 0.140 0.010 +0.229 +0.064

0.002 0.002 0.001 - 0.002 0.002 0.001 0.005 0.007

Full cubeful rollout with var.redn.

1296 games, Mersenne Twister dice gen. with seed 851744694 and quasi-random dice

Play: supremo 2-ply cubeful prune [world class]

keep the first 0 0-ply moves and up to 16 more moves within equity 0.32

Skip pruning for 1-ply moves.

Cube: 2-ply cubeful prune [world class]