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Subject: Re: Outside passer and candidate passer: definition wanted! :-)

Author: Robert Hyatt

Date: 11:57:46 02/27/06

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On February 27, 2006 at 10:10:30, Günther Simon wrote:

>On February 27, 2006 at 09:36:43, Alessandro Scotti wrote:
>
>>Thanks a lot Uri, this is an excellent definition to use in a program!
>>
>>On February 27, 2006 at 09:07:34, Uri Blass wrote:
>>
>>>definition is simply open pawn that is not a passed pawn and has a friendly pawn
>>>that can support it for every square in the promotion path that does not make it
>>>a passed pawn (for example white a4 b4 against black a6 but not white a5 b4
>>>against black a6 because a5 cannot support b5)
>>>
>>>Uri
>
>This is not always true. The pawn a5 can still support b5 sometimes.
>Here White still moves b5! and gets a supported passer on b6, because
>Black has to move its King nearer. As White is still in the square
>of Blacks passer it is an easy win for White.
>
>[D]8/8/p3k3/P6p/1P6/4K3/8/8 w - - 0 1
>
>Guenther


I call that a "hidden passer" in my passed pawn code.  The a pawn is passed,
because when white plays b5, if black takes the a-pawn runs and promotes first,
if black ignores it then either bxa6 or b6 and the b-pawn runs.  SO there is a
passer there that is not immediately obvious.  The closer to promotion this is,
the better, because black does get a passer in return, but it is much farther
away from the promotion square.



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