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Subject: Re: Detecting backward pawns

Author: Dave Gomboc

Date: 20:46:55 06/17/99

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On June 17, 1999 at 19:06:29, KarinsDad wrote:

>On June 17, 1999 at 18:26:40, Dave Gomboc wrote:
>
>>On June 17, 1999 at 14:42:44, KarinsDad wrote:
>>
>>>On June 17, 1999 at 13:32:19, Dave Gomboc wrote:
>>>
>>>>Imagine:
>>>>
>>>>White Ra1, Pa4, Pb4, Pc3
>>>>Black Ra8, Pa6, Pb5, Pc6
>>>>
>>>>The a6 pawn should be evaluated as either isolated or backward (depending on who
>>>>is to move), assuming other pieces do not interact with this configuration.
>>>>
>>>>Dave
>>>
>>>r..
>>>...
>>>p.p
>>>.p.
>>>PP.
>>>..P
>>>...
>>>R..
>>>
>>>The a6 pawn cannot be considered isolated unless black plays ba (which is not
>>>forced).
>>>
>>>The reason that it appears that the a6 pawn is backwards is due to the white
>>>rook having control of the a5 square indirectly (since white can play ab at any
>>>time). If black had another rook protecting his a8 rook, then the a6 pawn would
>>>not be considered backwards due to the a6 pawn not being pinned (i.e. the a6
>>>pawn could be pushed without the penalty of losing a pawn).
>>>
>>>I think that examples like this are excellent since they illustrate that some
>>>concepts are MUCH more complex than is readily apparent (and hence the need for
>>>a search engine).
>>>
>>>KarinsDad :)
>>
>>What I said wasn't exactly what I meant, but the main point is yeah, there's a
>>lot more going on than the obvious stuff.  More specifically regarding
>>backwardness, if it is Black's move, and allowing White to play ab would be bad,
>
>Why? 1. ab cb, what is white's follow up? If 2. c4 bc 3. Ra5 (3. b5 a5) c3, 4.
>Rc5 Rb8 and black has won a pawn and has 2 pawns to white's 1. ab is only good
>for white if black pushes a5, so black's a pawn is definitely backwards.

Again, I was speaking generally.  That's why I used "if".  I was not trying to
analyze the partial position.

Dave




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