Bring back original bonus

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 984a85a65e0492c3daaa46ddc72f06709ae32487..e17a3e340b939206662d259d8f58a42259585708 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -150,6 +150,8 @@ namespace {
 
   #undef S
 
+  const Score BishopPinBonus = make_score(66, 11);
+
   // Bonus for having the side to move (modified by Joona Kiiski)
   const Score Tempo = make_score(24, 11);
 
@@ -581,6 +583,11 @@ Value do_evaluate(const Position& pos, Value& margin) {
         // of threat evaluation must be done later when we have full attack info.
         if (ei.attackedBy[Them][PAWN] & s)
             score -= ThreatenedByPawnPenalty[Piece];
+        else if (Piece == BISHOP && (PseudoAttacks[Piece][pos.king_square(Them)] & s)) {
+             const Bitboard between = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
+             if (!more_than_one(between))
+                 score += BishopPinBonus;
+        }
 
         // Bishop and knight outposts squares
         if (    (Piece == BISHOP || Piece == KNIGHT)