Piece Values - PERK

Piece Evaluation by the Restricted King method

Example Values

Board Knight Bishop Rook Queen Chancellor
8x8 3.0904 3.1147 5.2893 9.0126 8.2326
10x8 3.1577 3.1414 5.4129 9.1584 8.4125

The Method

The Restricted King method is derived from the the conjecture by the mathematician, Taylor, published in a paper of 1876 that the value of a chess piece is proportional to its ability to safely check an enemy king on an otherwise vacant board.

I have never been entirely happy with this conjecture. From a practical point of view it cannot be used to assign values to pieces such as the Wazir, Ferz, Guard or Pawn. From a theoretical point of view the aim in most CVs is not to check the King, but rather to restrict the King's movement to zero (checkmate and stalemate).

So I thought it might be worth exploring the modified conjecture that the value of a chess piece is proportional to its ability to restrict the movement of an enemy king.



The basic measure of this restriction is to count, for every possible placement of piece and king, the number of squares of movement lost by the king due to attack from the piece plus the number of moves the king would have had, had it occupied the piece's position.

The basic count is illustrated by the image on the right. For this single position the Bishop scores a count of 2 for denying the King access to the two suares marked with a dot.

This count is then modified.





to be continued

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