Position # 47

[PersianLord]

Position information:

Pip-count: Red 78-125 White
Score:      Red   3-4   White
Match:              5-pointer

Position ID: Dq+JAxCzbZsAAA , Match ID: 8Am1AEAAGAAA

Spoiler

The best move here is again very score-dependant. Red is 2-away, while white is 1-away, so gammons are of utmost taste for red and meaningless for white. Thus, red should play as aggressive as he can to finish white off with a gammon. The quickest way to gammon white is to close him out NOW, because right now white has lots of men to bear in home and if red manages to achive a safe bear-off, white's survival will be very ulikely. To do this, red should not wait for a better opportunity for hit and make the 2-pt, because that gives white time to (a) build a better home and (b) bear-in more men, i.e. reducing the chances of getting gammoned. So hit the trapped man NOW (7/2*). But what to do with the 2?

-10/8 : Maintains the prime to some extent, but inadequate builders to make the 2-pt

-8/6 : The most aggressive play with lots of builders, but breaks the prime and lots of return shots for whitt.

-4/2 : It's a good idea because it brings the man on the 10-pt into play, but it's too risky if white gets a 4 because he will have no trouble afterwards, jumping out of the prime.

- 7/5 : The best move: it provides enough builders, but not too risky if hit. After entering, white will get into safety, just in case he rolls a 5 and, considering his weak board, red should be able to enter and re-hit.


    1. Cubeful 2-ply    7/5 7/2*                     Eq.:  +2.186
        91.7%  67.6%   0.7% -   8.3%   1.3%   0.0%       
    2. Cubeful 2-ply    8/6 7/2*                     Eq.:  +2.118 ( -0.068)
        88.7%  67.2%   0.6% -  11.3%   2.7%   0.1%
       
    3. Cubeful 2-ply    10/8 7/2*                    Eq.:  +2.099 ( -0.087)
        90.2%  64.7%   0.6% -   9.8%   1.5%   0.0%
       
    4. Cubeful 2-ply    7/2* 4/2                     Eq.:  +2.082 ( -0.104)
        88.8%  65.3%   0.5% -  11.2%   2.1%   0.1%
     
    5. Cubeful 2-ply    10/3                         Eq.:  +1.870 ( -0.316)
        91.7%  51.8%   0.4% -   8.3%   0.9%   0.0%
       

Note that the safe (here it's more cowardly) move of 10/3 wins as many simple wins as the 1st move, but it wins a lot less gammons and that counts.

But what if it was a DMP match? In the DMP, safety is the best choice, so the non-hitting move of 10/3 which maintains the 6-pt prime comes at best:

1. Cubeful 2-ply    10/3                         Eq.:  +0.881
        94.0%  35.8%   0.1% -   6.0%   0.1%   0.0%   
   
    2. Cubeful 2-ply    8/6 8/3                      Eq.:  +0.863 ( -0.018)
        93.1%  35.7%   0.1% -   6.9%   0.2%   0.0%
   
    3. Cubeful 2-ply    7/5 7/2*                     Eq.:  +0.845 ( -0.035)
        92.3%  65.9%   0.7% -   7.7%   0.8%   0.0%
       
    4. Cubeful 2-ply    10/8 7/2*                    Eq.:  +0.816 ( -0.064)
        90.8%  62.8%   0.7% -   9.2%   1.1%   0.0%
       
    5. Cubeful 2-ply    10/5 8/6                     Eq.:  +0.780 ( -0.101)
        89.0%  39.4%   0.2% -  11.0%   0.3%   0.0%
       

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[Zorba]

For the record, it appears to be the Crawford game, so no cube in play.

[sixty_something]

nice analysis, PL

Spoiler

i opted, as usual, for the more aggressive 8/6 7/2*

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