Adjust history threshold for quiet moves futility pruning

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index e3a5a92e6c7802457e0cc2a64477938914412f96..f5887f3fda78fc1f6d879008b09d5f0e1ff5df8b 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1006,7 +1006,8 @@ moves_loop: // When in check, search starts from here
                   && ss->staticEval + 235 + 172 * lmrDepth <= alpha
                   &&  (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
-                    + (*contHist[3])[movedPiece][to_sq(move)] < 27400)
+                    + (*contHist[3])[movedPiece][to_sq(move)]
+                    + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 31400)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)