diff --git a/src/evaluate.cpp b/src/evaluate.cpp index dd5d23b2..c945cf53 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -791,11 +791,13 @@ namespace { unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them); // If there are no enemy pieces or attacks on passed pawn span, assign a big bonus. + // Or if there is some, but they are all attacked by our pawns, assign a bit smaller bonus. // Otherwise assign a smaller bonus if the path to queen is not attacked // and even smaller bonus if it is attacked but block square is not. - int k = !unsafeSquares ? 35 : - !(unsafeSquares & squaresToQueen) ? 20 : - !(unsafeSquares & blockSq) ? 9 : + int k = !unsafeSquares ? 36 : + !(unsafeSquares & ~attackedBy[Us][PAWN]) ? 30 : + !(unsafeSquares & squaresToQueen) ? 17 : + !(unsafeSquares & blockSq) ? 7 : 0 ; // Assign a larger bonus if the block square is defended