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Backgammon => Backgammon problems => Topic started by: PersianLord on November 26, 2008, 09:25:34 PM

Poll
Question: Red to play 6-5
Option 1: 21/10 votes: 1
Option 2: 21/16-21/15 votes: 9
Option 3: 11/5-8/3 votes: 2
Option 4: 21/16-8/2 votes: 1
Option 5: 21/16-11/5 votes: 0
Title: Position # 49
Post by: PersianLord on November 26, 2008, 09:25:34 PM
Position information:

Pip-counts: Red 107-98 White
Score : Red 0-0 White
Match : 5-pointer

Red to Play 6-5

(http://1.bp.blogspot.com/_nvjbHZxa_5Y/SS22_8m2N3I/AAAAAAAAAEs/xypjovHxxZ0/s400/problem49.png)

Spoiler


Position ID: ZO8+AADL9kQABg , Match ID: cIm6AAAAAAAA

The aggressive player might stay back to get a shot, but it's a big blunder. Right now, red has substantial potentials for a pure racing game, because even though white has a slim advantage in pip-counts, red is leading in bear-ins. Thus red should jump over the white's 4-pt prime with both of his back men.

1. Cubeful 2-ply    21/16 21/15                  Eq.:  -0.145
        45.0%   0.0%   0.0% -  55.0%   0.0%   0.0%
        2-ply cubeful prune [world class]   
2. Cubeful 2-ply    11/5 8/3                     Eq.:  -0.489 ( -0.344)
        34.1%   0.8%   0.0% -  65.9%   2.5%   0.1%
        2-ply cubeful prune [world class]
    3. Cubeful 2-ply    21/16 8/2                    Eq.:  -0.510 ( -0.365)
        33.2%   2.4%   0.0% -  66.8%   3.9%   0.1%
        2-ply cubeful prune [world class]
    4. Cubeful 2-ply    21/16 11/5                   Eq.:  -0.554 ( -0.409)
        31.8%   2.5%   0.0% -  68.2%   5.2%   0.2%
        2-ply cubeful prune [world class]
    5. Cubeful 2-ply    21/10                        Eq.:  -0.562 ( -0.416)
        31.3%   2.5%   0.0% -  68.7%   4.5%   0.2%
        2-ply cubeful prune [world class]


As it's shown in GNUBG's analysis, even after running, red is still the underdog, but with a so much little margin that makes it theoretically incorrect for white even to dare to throw the cube.

(PL, i replace the tab characters which sometimes get interpreted and displayed as a meaningless   with a single space to improve the readability .. otherwsie, a fine problem and analysis .. sixty)
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Title: Re: Position # 49
Post by: PersianLord on November 26, 2008, 09:43:09 PM
Spoiler


Position ID: ZO8+AADL9kQABg , Match ID: cIm6AAAAAAAA

The aggressive player might stay back to get a shot, but it's a big blunder. Right now, red has substantial potentials for a pure racing game, because even though white has a slim advantage in pip-counts, red is leading in bear-ins. Thus red should jump over the white's 4-pt prime with both of his back men.

  1. Cubeful 2-ply    21/16 21/15                  Eq.:  -0.145
        45.0%   0.0%   0.0% -  55.0%   0.0%   0.0% 
     
    2. Cubeful 2-ply    11/5 8/3                     Eq.:  -0.489 ( -0.344)
        34.1%   0.8%   0.0% -  65.9%   2.5%   0.1%
       
    3. Cubeful 2-ply    21/16 8/2                    Eq.:  -0.510 ( -0.365)
        33.2%   2.4%   0.0% -  66.8%   3.9%   0.1%
       
    4. Cubeful 2-ply    21/16 11/5                   Eq.:  -0.554 ( -0.409)
        31.8%   2.5%   0.0% -  68.2%   5.2%   0.2%
       
    5. Cubeful 2-ply    21/10                        Eq.:  -0.562 ( -0.416)
        31.3%   2.5%   0.0% -  68.7%   4.5%   0.2%
       


As it's shown in GNUBG's analysis, even after running, red is still the underdog, but with a so much little margin that makes it theoretically incorrect for white even to dare to throw the cube.


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