diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 40630d22..fad2a785 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -308,11 +308,12 @@ namespace { if (Pt == BISHOP) { // Penalty according to number of pawns on the same color square as the - // bishop, bigger when the center files are blocked with pawns. + // bishop, bigger when the center files are blocked with pawns and smaller + // when the bishop is outside the pawn chain. Bitboard blocked = pos.pieces(Us, PAWN) & shift(pos.pieces()); score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s) - * (1 + popcount(blocked & CenterFiles)); + * (!bool(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles)); // Bonus for bishop on a long diagonal which can "see" both center squares if (more_than_one(attacks_bb(s, pos.pieces(PAWN)) & Center))