diff --git a/src/search/negamax.rs b/src/search/negamax.rs
index 890fe4d..ca518a9 100644
--- a/src/search/negamax.rs
+++ b/src/search/negamax.rs
@@ -54,7 +54,9 @@ pub fn negamax(
         }
     }
 
-    if plies != 0 && !in_check && depth >= 3 && do_nmp && game.board.non_pawn_materials() > 0 {
+    let non_pv = beta == alpha + 1;
+
+    if non_pv && plies != 0 && !in_check && depth >= 3 && do_nmp && game.board.non_pawn_materials() > 0 {
         game.make_null_move();
         let score = -negamax(
             game,