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Subject: Re: Tough solution

Author: Amir Ban

Date: 02:35:18 01/15/98

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On January 14, 1998 at 21:18:23, Robert Hyatt wrote:

>On January 14, 1998 at 16:53:06, Vincent Lejeune wrote:
>
>>I've red a book chess problem, and find the following position :
>>
>>[Event "?"]
>>[Site "?"]
>>[Date "??.??.????"]
>>[Round "?"]
>>[White "W"]
>>[Black "B"]
>>[Result "*"]
>>[WhiteElo "?"]
>>[BlackElo "?"]
>>[FEN "8/7p/6pP/k4pP1/b1p1pP2/KpPpP3/1P1P4/7Q w - - 0 1"]
>>
>>
>>and the book say :
>>
>>If it's white to moves, black are in zugzwang because after :
>>1.Qd1 B moves 2.Qxc3 cxb3 3.Kxd3 , the 2 passed pawn win for white !!!
>>I don't understand everything in the position (and I don't blame who
>>don't understand like me ;)  ).
>>
>>I look for someone who can analyse this position with a strong chess
>>program...
>>
>>Thanks in advance.
>>
>>Vincent
>
>here's Crafty's analysis:
>
>              depth   time  score   variation (1)
>               11->   0.58   7.31   Qg2 Bc6 Qg3 Kb5 Qh4 Kc5 Qf2 Kb5 Qg3
>                                    Kc5 Qg2
>               12     0.63   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Kc5 Qf2 Kb5 Qg3
>                                    Kc5 Qg2 <HT>
>               12->   0.71   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Kc5 Qf2 Kb5 Qg3
>                                    Kc5 Qg2 <HT>
>               13     0.77   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Bd5 Qh2
>                                    Bc6 Qh4 Kb5 Qf2 Kc5 <HT>
>               13->   0.92   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Bd5 Qh2
>                                    Bc6 Qh4 Kb5 Qf2 Kc5 <HT>
>               14     0.97   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Bd5 Qh2
>                                    Bc6 Qh4 <HT>
>               14->   4.59   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Bd5 Qh2
>                                    Bc6 Qh4 <HT>
>               15     5.40   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Kc5 Qh4 Bd5 Qg3 Bc6 Qf2 <HT>
>               15->   5.48   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Kc5 Qh4 Bd5 Qg3 Bc6 Qf2 <HT>
>               16     6.07   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh4 Kb5 Qf2 Kc5 Qg2 Kd5
>               16->  26.65   7.29   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh4 Kb5 Qf2 Kc5 Qg2 Kd5
>               17    27.16   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Kb5 Qg3 Kc5 Qh4 Bd5 Qf2 Kd6
>               17->  28.09   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Kb5 Qg3 Kc5 Qh4 Bd5 Qf2 Kd6
>               18    31.43   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Kb5 Qh1 Kc5 Qg2 Bd5 Qg3 Kd6
>               18->  34.79   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Kb5 Qh1 Kc5 Qg2 Bd5 Qg3 Kd6
>               19    36.22   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Bd5 Qg3 Ba8 Qf2 Bd5 Qg1 Kb5
>                                    Qf2 Kc5
>               19->   1:00   7.30   Qg2 Bc6 Qg3 Kb5 Qh4 Ka5 Qf2 Kb5 Qh2
>                                    Ka5 Qh3 Bd5 Qg3 Ba8 Qf2 Bd5 Qg1 Kb5
>                                    Qf2 Kc5
>certainly seems to be winning...

You mean because black looks at the score and resigns ?

This position looks to me truely unsolvable, tactically or positionally.
The main problem is that even after the sacrifice on b3 it's a long way
to seeing a win (I am taking the book's word on it, it's not obvious to
me).

I think the only hope to solve here is if we are able to assign a plus
score to the position after Qxb3. If we have this, we still need the
hash to conclude that shuffling the queen is a draw, which doesn't look
easy either.

Just offhand, I don't see any basis for having a plus score for the Q
sac on b3. Such positions with the same piece & pawn configuration are
almost always a dead loss for white.

Maybe we can break the problem into two easier parts:

- Who sees a plus score for Qxb3 ?
- Who sees a draw score for only shuffling the queen ?

Amir



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