More futility pruning

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 075be835a1aa575f624b1fa2418815b54f67b6c5..a712ce87bb77feca94399d739367e7049e98f3b1 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -813,7 +813,7 @@ namespace {
     if (   !PvNode
         &&  depth < 9
         &&  eval - futility_margin(depth, improving) >= beta
-        &&  eval < VALUE_KNOWN_WIN) // Do not return unproven wins
+        &&  eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins.
         return eval;
 
     // Step 8. Null move search with verification search (~40 Elo)