X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=02810b78490093f1f14f7c220897f2661f4bc63f;hp=984a85a65e0492c3daaa46ddc72f06709ae32487;hb=ea4e22be1da1ccbf316d27f2eb3b14d0e13388e4;hpb=a72710c66038f3c5abc8ba84d6a36c49c55d1b6c

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 984a85a6..02810b78 100644
--- 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);
 
@@ -496,7 +498,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
 
     // Init king safety tables only if we are going to use them
     if (   pos.piece_count(Us, QUEEN)
-        && pos.non_pawn_material(Us) >= QueenValueMg + RookValueMg)
+        && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
     {
         ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
         b &= ei.attackedBy[Us][PAWN];
@@ -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)