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Subject: Re: Poor assessment by Crafty 16.14

Author: José de Jesús García Ruvalcaba

Date: 13:56:25 07/27/99

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On July 27, 1999 at 15:06:41, Robert Hyatt wrote:

>On July 27, 1999 at 14:07:22, Dave Gomboc wrote:
>
>>Last night I reached the following position as White in the blitz portion of a
>>game/30:
>>
>>White: Kg2, Qd5, pawns on b3, f2, g3, h4.
>>Black: Kf6, Qe5, pawns on b4, g7, h7.
>>White to move.
>>
>>I played 43. Qc6+, and my opponent blundered with 43...Qe6??  I went on to win
>>the pawn ending after 44. Qxe6+ Kxe6 45. Kf3.
>>
>>Flipping through the game with Crafty, I noticed that it also liked 43...Qe6.
>>In fact, it holds this move until at least depth=16.  (I didn't let it analyze
>>further, but really, this should be seen at depth far less than 16.)  It clearly
>>doesn't realize just how winning White's position is after the queen trade.
>>
>>Another test position for Bob's collection?
>>
>>Dave
>
>
>It will understand this before long.  It already understands 'outside passed
>pawns' quite well... but at present, it doesn't understand that pawn majority
>turns into outside passer later on.

	Crafty is not the only program with this weakness. And it can be exploited by
humans who are aware of it. I once swindled a draw against crafty from a very
inferior ending, using this weakness. Crafty preferred to have a central passed
pawn which was easy to block, instead of an outside pawn majority which
eventually would lead to an outside passed pawn (but it would require a very
deep search to see that). I have seen similar mistakes a lot of times in
comp-comp games.
José.




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