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Subject: Re: Discrete Movements in Chess (revisited)

Author: Dan Ellwein

Date: 14:13:12 12/16/99

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On December 16, 1999 at 16:10:20, Bo Persson wrote:

>On December 16, 1999 at 10:59:48, Dan Ellwein wrote:
>
>>My original post came about as a result of wanting to know how many unique
>>movements there are in chess (or at least have a rough idea).
>>
>>Chess, being the complex game it is, I wanted to see just how many unique
>>movements this complexity was based on.
>>
>>What came to mind for consideration were the following:
>>
>>the movements of the 32 pieces
>>special moves like castling and en-passant
>>pawn moves being different from pawn captures
>>pawns being able to move 2 squares on the first move
>>and pawn promotion (although this may not apply)
>>
>>(there may be other possibilities to consider)
>
>Also,
>the Queen is very powerful, but alone and also very vulnerable
>the Rooks are not quite as strong, but there is two of them!
>the Knights can jump over other pieces, their attacks are hard to block. So is
>their movement
>the Pawns are weak, but they are many and work good in teams
>the two Bishops are equal, but also different (square colors). Potential for
>team work with many other pieces. Long range and lower value is good for
>support.
>the King is often threatened, but can move in any direction. It is also very
>strong in the end game, where it can block its opponent.
>
>An extremely successful mix!
>
>
>The complexity is not only in the different "movements", but also in forming
>groups of pieces where each "character" can use its own special abilities to
>support the others, working together towards a common goal.
>
>Hm, an interesting thought there...  :-)
>

yes... agree... it's actually the interaction of the movements that give rise to
the complexity found in chess and not the movements themselves...

the 32 pieces reducing down to 6 (K,Q,R,B,N,P) combine to make-up 32 major
groups...

K  KP KN KB KR KQ  KPN KPB KPR KPQ KNB KNR KNQ KBR KBQ KRQ  KPNB KPNR KPNQ KPBR
KPBQ KPRQ KNBR KNBQ KNRQ KBRQ  KPNBR KPNBQ KPNRQ KPBRQ KNBRQ  KPNBRQ

>
>Since pawns do move differently than the way they capture, I decided to use as
>>one of my parameters for movement - Type.
>>
>>I came up with 3 types of movement which I called:  Capture/NonCapture,
>>NonCapture Only, and Capture only.
>
>or, possibly, "Piece moves", "Pawn moves" and "Pawn captures"? (forgetting about
>castling for a moment, and separating the pawns from the major pieces).
>
>>Capture/NonCapture would include all the pieces except for the pawn.
>>
>>NonCapture Only would include the pawn moves (including the option of the pawn
>>moving 2 squares on its first move)
>
>slightly different from the castling (where the king and the rook make their
>combined first move), the pawn can make a double move *from its original
>location*. Ok, so it's only a small difference, but the pawns state can be
>deduced from its position (2nd row), while you have to keep track of king and
>rooks, as they could have moved previosuly and returned to there start position.
>
>> and castling (since a capture cannot occur on this move).
>
>No, but some other *very* special conditions apply, like some squares must be
>empty, and some squares must not be attacked by the opponent. Not to mention
>that two pieces that haven't even moved *once* before, suddenly move both at the
>same time. And they are passing thru (or over?) each other!
>
>>Capture Only would only include the pawn.  En-passant would be covered in this
>>category.
>>
>>Also, since, pieces can move more than one square on a move (moving from one end
>>of the board to the other end a piece travels 7 squares), I decide to use as
>>another parameter of  movement - Magnitude.
>>
>>Since chess is played on an 8x8 board, Magnitude would have a maximum limit of
>>7.
>>
>>So, Movement, then, (at least for my purposes) is a funtion of Type and
>>Magnitude.
>>
>>Type - having three categories: Capture/NonCapture, NonCapture Only, and Capture
>>Only.
>>
>>Magnitude - ranging from 1 (square) to 7 (squares).
>>
>>Looking at the 32 pieces we have the following:
>>
>>K's - 2
>>Q's - 2
>>R's - 4
>>B's - 4
>>N's - 4
>>P's -16
>>
>>So, from the 32 pieces, 6 pieces need to be considered - K,Q,R,B,N,P
>>
>>From these 6 pieces, 4 need to be looked at due to the Rook and Bishop movements
>>are incorporated into the Queen.
>>
>>So now we have - K, Q(which includes the Rook and Bishop), N, P
>
>Yes, some programs (like Crafty) keeps track of the combined piece types
>Rooks_and_Queens and Bishops_and_Queens to use in places like attack detection.
>
>>And this is how I came up with my table and came up with there being 11 unique
>>(discrete) movements in chess.
>>
>>If, instead of Magnitude having a range of 1 to 7, but we give it a range of 0
>>to 7, then pawn promotion could be considered also.  Replacing a pawn with
>>either a Q,R,B,N does not involve a movement (the Q,R,B,or N is placed on the
>>same square as the pawn was on - the actual promotion requires no movement).
>>
>>In this case there would be 12 unique movements in chess, and these 12 movements
>>would be what gives chess its complexity.
>>
>>PilgrimDan
>
>
>
>Still fascinated by the thoughts, but don't (yet?) know how to use it.
>
>
>Bo Persson
>bop@malmo.mail.telia.com



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