More extensions if SE search is very low.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 99c2b09f9ef42b4032c95864e7f4e0e497147ec5..5542fc87366a0923a5f2122ad91144c0def70a1f 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1130,6 +1130,8 @@ moves_loop: // When in check, search starts from here
           {
               extension = 1;
               singularQuietLMR = !ttCapture;
+              if (!PvNode && value < singularBeta - 140)
+                  extension = 2;
           }
 
           // Multi-cut pruning