King Pawn Tropism

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King Pawn Tropism,
an endgame evaluation feature concerning the distance of a king to pawns, with the motivation to either defend or support own ones, or to attack or block opponent ones - in both cases, the closer the better.


A common way to implement tropism is to calculate the average Manhattan-distance of the king square to all pawn squares, weighted by some factor to consider passed and weak pawns (i.e. 6:3:2 for passers, backward and remaining pawns as applied in Bobby and also Kraas' and Schrüfer's didactic Basic program Demoschach, described in Das große Computerschachbuch [1]). Two accumulators are used to aggregate all the Manhattan-distances times weight, and all the weights as well, to finally divide the weighted sum of distances by the number of pawn weights for an average distance


in the 1..14 Manhattan range, somehow interpreted as penalty for the king side.

See also

External Links


  1. Rainer Bartel, Hans-Joachim Kraas, Günther Schrüfer (1985). Das große Computerschachbuch. Data Becker, ISBN 3-89011-117-3 (German),, pp. 258, Verfahren zur Bewertung der Königsaktivität, 2. Mittlerer Abstand zwischen König und Bauern

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