Mop-up Evaluation

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Home * Evaluation * Game Phases * Endgame * Mop-up Evaluation

Mop-up Evaluation might be applied at decided late endgame positions without any pawns, where one side has a winning advantage to checkmate and likely a rook or queen (or even two different colored bishops). The winning side wants to drive the losing king to the edges and corners, and has therefor a bonus for Center distance (Center Manhattan-distance) of the losing king, and a bonus for a minimum distance of both kings. In practice one often uses some term based on the (weighted) sum of the Chebyshev distance and the Manhattan distance, to have a higher bonus for the corners and straight rather than diagonal opposition.

Chess 4.x

For instance, Chess 4.x Mop-up evaluation was based on sum of absolute rank- and file-distances [1], something like this (ignoring knights, which were equally considered like the king) from the stronger side of view:

PosEval = 4.7 * CMD + 1.6 * (14 - MD)

CMD is the Center Manhattan distance of the losing king and MD the Manhattan distance between both kings. Of course part of such terms might be covered by piece-square tables of that very late game stage, and most of these positions are handled by interior node recognizer nowadays.

See also

Forum Posts


  1. David Slate, Larry Atkin (1977). CHESS 4.5 - The Northwestern University Chess Program. Chess Skill in Man and Machine, reprinted (1988) in Computer Chess Compendium

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