X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=67c98709521ae5d63707a56d39a2f63b2a010d41;hp=f5552e7887dcd4e03a3a243a747193917e0cbece;hb=42de93ac15366d6d20c1b2fbf99b4780e8ac6617;hpb=426f55b78d8d83ad779772dc46ad4f645177c4c4

diff --git a/src/search.cpp b/src/search.cpp
index f5552e78..67c98709 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1378,6 +1378,10 @@ namespace {
 
         if (nullValue >= beta)
         {
+            // Do not return unproven mate scores
+            if (nullValue >= value_mate_in(PLY_MAX))
+                nullValue = beta;
+
             if (depth < 6 * OnePly)
                 return nullValue;