Changes

Written by Marc-François Baudot, in association with Jean-Christophe Weill of [[Cumulus]] (they collaborate on ideas and code, but have different programs reflecting their different opinions and experiments. Échec's [[Evaluation functionFunction|evaluation function]] includes [[Piece-Square Tables|piece placement]] relative to [[Pawn Structure|pawn structure]], pawn structure itself, taking into account of which major or minor pieces are on the board, [[Mobility|mobility]], etc. (Marc reports that this was badly tuned, with the result that Échec's positional play was poor in the tournament). [[Search]] techniques include [[Check Extensions|check extensions]] but not [[Singular Extensions|singular extensions]], plus extensions for some mate threats and [[Promotions|promotion]].