Use alpha instead of beta-1

It is more directly related to a fail-low.

No functional change.

diff --git a/src/search.cpp b/src/search.cpp
index 1268445..00c871f 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -716,7 +716,7 @@ namespace {
                 && (ss-1)->reduction
                 && threatMove != MOVE_NONE
                 && allows(pos, (ss-1)->currentMove, threatMove))
-                return beta - 1;
+                return alpha;
         }
     }