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Subject: Re: vhard test set, after the key move has been made -- some refuted.

Author: Uri Blass

Date: 12:01:43 11/09/05

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On November 09, 2005 at 14:36:07, Uri Blass wrote:

>On November 09, 2005 at 13:03:43, Dann Corbit wrote:
>
>>Following up on an idea from Uri Blass about analyzing positions after the key
>>move has been made, I did another look at the hard positions posted recently.
>>
>>Given the following test set, which is taken from the vhard test set posted
>>yesterday AFTER the key move has been made, it appears that some of the problems
>>are (or may be) busted.  Each problem should have a large and negative score
>>after deep analysis and yet some of them are clearly winning.
>
>The only position that you may consider as refuted is the position with Nf6+ and
>even this is not refuted if you look at the following post that explained the
>solution
>
>http://www.talkchess.com/forums/1/message.html?460352
>
>
>solution is hard to find for chess programs and top chess programs simply prune
>so much that they cannot find the idea even after the correct move.
>
>It is easy to use yace for retrogrede analysis of the relevant position to show
>that white is winning.
>
>Uri

Note that in the case of this problem there are some moves in the pv that are
hard to find

[Event "4320'/1"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]
[PlyCount "9"]
[TimeControl "1/259200:0/0:0/0"]

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 *


Not only 1.Nf6+ is hard to find but also
3.Bc2+ and 4.d8=Q

It is espacially correct for fruit that has no mate extensions.

Uri



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