X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=66ef5043d28e2280d286509cf2aaee482677e190;hp=56b56733fb2771aa998030887370622a408ff786;hb=285bf7041ad214156188823eb9118e6af7f4b2e4;hpb=b5781150ea8557e2030f8bc8b4eadede0ecec6bd

diff --git a/src/search.cpp b/src/search.cpp
index 56b56733..66ef5043 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1161,7 +1161,7 @@ moves_loop: // When in check, search starts from here
           if (thisThread->ttHitAverage > 509 * TtHitAverageResolution * TtHitAverageWindow / 1024)
               r--;
 
-          // Reduction if other threads are searching this position
+          // Increase reduction if other threads are searching this position
           if (th.marked())
               r++;
 
@@ -1169,7 +1169,8 @@ moves_loop: // When in check, search starts from here
           if (ss->ttPv)
               r -= 2;
 
-          if (!PvNode && depth > 10 && thisThread->bestMoveChanges <= 2)
+          // Increase reduction at root and non-PV nodes when the best move does not change frequently
+          if ((rootNode || !PvNode) && depth > 10 && thisThread->bestMoveChanges <= 2)
               r++;
 
           if (moveCountPruning && !formerPv)