Tweak cutnode reduction

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6ec4d80322372332e10f909a5c574dbf6be5f3d9..91ac60ad4b2615f47864631e139b1108a4266012 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1167,6 +1167,13 @@ moves_loop: // When in check, search starts from here
       {
           Depth r = reduction(improving, depth, moveCount);
 
+          // Decrease reduction at non-check cut nodes for second move at low depths
+          if (   cutNode
+              && depth <= 10
+              && moveCount <= 2
+              && !ss->inCheck)
+              r--;
+
           // Decrease reduction if the ttHit running average is large
           if (thisThread->ttHitAverage > 473 * TtHitAverageResolution * TtHitAverageWindow / 1024)
               r--;