Further improve history updates

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6affa5107b0cfe6544c60ac4ab66b128be0c7d73..ed5dd6c2c7ad5aab3e39b26cb038833c3a6b58d2 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1325,7 +1325,7 @@ moves_loop: // When in check, search starts here
     // Bonus for prior countermove that caused the fail low
     else if (   (depth >= 3 || PvNode)
              && !priorCapture)
-        update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth + (PvNode || cutNode)));
+        update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + (PvNode || cutNode)));
 
     if (PvNode)
         bestValue = std::min(bestValue, maxValue);