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Just another cube decision - RO

Posted By: Daniel Murphy
Date: Sunday, 20 November 2011, at 9:54 p.m.

In Response To: Just another cube decision (Daniel Murphy)

Thank you everyone for your comments.

The score (after 0 games) is: mochy 0, sonrik 0 (match to 11 points)

Move number 30: sonrik on roll, cube decision?

mochy	132
sonrik	113
Position ID: 1roBwANsdmMhAA Match ID: cAlgAQAAAAAE

OTB Sondre doubled and Mochy passed.

Cube decision
Rollout cubeless equity		+0.5755	(Money: +0.5743)
Cubeful equities:
1.	Double, pass	+1.0000
2.	Double, take	+1.0560	+0.0560
3.	No double	+0.9867	-0.0133
Proper cube action:		Double, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.7713 0.0492 0.0011 - 0.2287 0.0181 0.0005 +0.5755 +0.9867 Standard error 0.0009 0.0009 0.0002 - 0.0009 0.0006 0.0002 0.0020 0.0052 Player mochy owns 2-cube 0.7811 0.0456 0.0010 - 0.2189 0.0162 0.0005 +1.1972 +1.0560 Standard error 0.0011 0.0012 0.0003 - 0.0011 0.0008 0.0002 0.0047 0.0063
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 932367913 and quasi-random dice
Play: world class 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

A 5 point holding game down 113-132 pips. Many such positions would be clear takes.

But compared to a "typical" holding game, a satisfactory example of which Tim posted, Blue stands a lot better here. His position with the two outfield blots only appears to be loose; those two checkers are in little danger because only indirect rolls hit them and White has a poor board. Blue effectively has two rolls to safety those blots. After that, Blue's biggest problem will be to clear the 11 point. But he'll have 7 other checkers to play with (all the other checkers now in the outfield) before being forced to play from the 11 point. In the "typical" position that Tim threw together, Blue has only 3 outfield spares to play with before being forced to play from either the 8 point or the 13 point. The made bar point makes a difference, too.

Also, as Casper mentioned, White has 4 checkers on the 20 point. All else being equal with regard to race, boards, and points to clear, I believe these holding games tend to be worse for the underdog when he has more than two checkers on his anchor.

Gnubg 2-ply would have taken:

Annotation

Cube analysis
2-ply cubeless equity +0.5501 (Money: +0.5497)
0.7620 0.0431 0.0007 - 0.2380 0.0180 0.0003
Cubeful equities:
1. Double, take +0.9485
2. Double, pass +1.0000 ( +0.0515)
3. No double +0.9066 ( -0.0420)
Proper cube action: Double, take

Messages In This Thread

• Just another cube decision
  Daniel Murphy -- Saturday, 19 November 2011, at 5:13 p.m.
  • Just another cube decision
    David Rennie -- Saturday, 19 November 2011, at 5:44 p.m.
  • Just another cube decision
    Timothy Chow -- Saturday, 19 November 2011, at 7:49 p.m.
    • Just another cube decision
      Mr Majestyk -- Sunday, 20 November 2011, at 12:32 a.m.
      • Just another cube decision
        Timothy Chow -- Sunday, 20 November 2011, at 1:31 a.m.
        • Just another cube decision
          David Rennie -- Sunday, 20 November 2011, at 2:02 a.m.
          • Some bot info
            Timothy Chow -- Sunday, 20 November 2011, at 7:37 p.m.
  • Just another cube decision
    Kevin Whyte -- Sunday, 20 November 2011, at 2:19 a.m.
  • Just another cube decision
    Casper van der Tak -- Sunday, 20 November 2011, at 7:17 a.m.
  • Just another cube decision
    David Kettler -- Sunday, 20 November 2011, at 4:27 p.m.
  • Just another cube decision - RO
    Daniel Murphy -- Sunday, 20 November 2011, at 9:54 p.m.
    • Just another cube decision - RO
      Casper van der Tak -- Monday, 21 November 2011, at 9:18 a.m.
      • Just another cube decision - RO
        Timothy Chow -- Monday, 21 November 2011, at 3:29 p.m.