Do not razor after a null move

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 67369ad5655d37656b869b23e1f0cbfa12781479..3838375fa5517029f5c9d6e1b38018d83a490249 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1309,6 +1309,7 @@ namespace {
     else if (   !value_is_mate(beta)
              && depth < RazorDepth
              && approximateEval < beta - RazorApprMargins[int(depth) - 2]
+             && ss[ply - 1].currentMove != MOVE_NULL
              && ttMove == MOVE_NONE
              && !pos.has_pawn_on_7th(pos.side_to_move()))
     {