Tweak RestrictedPiece bonus

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index fad0771db4aa3e04f1be929f70443f34c7d8b536..a1a3b4ed267c6293f135e9fdef1b2c5beea3a82d 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -520,11 +520,11 @@ namespace {
     }
 
     // Bonus for restricting their piece moves
+    // Greater bonus when landing square is occupied
     b =   attackedBy[Them][ALL_PIECES]
        & ~stronglyProtected
        &  attackedBy[Us][ALL_PIECES];
-
-    score += RestrictedPiece * popcount(b);
+    score += RestrictedPiece * (popcount(b) + popcount(b & pos.pieces()));
 
     // Protected or unattacked squares
     safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];