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Subject: Re: passed pawn evaluation.

Author: Robert Hyatt

Date: 10:05:38 01/12/04

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On January 12, 2004 at 10:24:59, scott farrell wrote:

>On January 12, 2004 at 05:52:07, Tord Romstad wrote:
>>On January 11, 2004 at 21:18:30, macaroni wrote:
>>>I have recently been fiddling arround with some passed pawn code, however I just
>>>can't seem to get it working very well. Can you give me an idea of what sort of
>>>values you give different types (in different stages) of passed pawns?
>>Here is a rough description of what I do:
>>Start by giving the passed pawn a bonus depending on which rank it occupies.
>>You then adjust this bonus depending on the placement of the other pieces
>>on the board.  Some examples:
>>Protected passed pawns and passed pawn duos are especially dangerous.
>>Adjust the bonus up if there is a friendly pawn beside or diagonally
>>behind the passed pawn.
>>Adjust the bonus up if there is a friendly rook behind the pawn, and down if
>>there is an enemy rook behind it.
>this is where you need to be careful if you have a pawnhash, you cant hash in
>other pieces :) you have to put it into the rook/king eval instead.


Everybody needs to debug _that_ problem at least once.  Some of us more
than once.  :)

>>A passed pawn is usually more dangerous if it is supported by a king.
>>Increase the bonus if the friendly king is close, especially if it is
>>somewhere in front of the pawn.  Likewise, you should increase the bonus
>>if the enemy king is far away.  In rook endgames, it is probably a good
>>idea to further increase the bonus if the enemy king is cut off by
>>a rook (I don't do this yet, but I plan to add it in the near future).
>>Passed pawns are most dangerous if they are able to advance safely.
>>If the passed pawn is blocked by an enemy piece, adjust the bonus down.
>>If it is unblocked, increase the bonus if your static exchange evaluator
>>decides that it is safe to push the pawn, and reduce the bonus if it is
>>not safe to push it.

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