diff --git a/src/search.cpp b/src/search.cpp
index 0e82f04e..c7b00766 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1489,7 +1489,7 @@ moves_loop: // When in check, search starts here
     // to search the moves. Because the depth is <= 0 here, only captures,
     // queen promotions, and other checks (only if depth >= DEPTH_QS_CHECKS)
     // will be generated.
-    Square prevSq = (ss-1)->currentMove != MOVE_NULL ? to_sq((ss-1)->currentMove) : SQ_NONE;
+    Square prevSq = is_ok((ss-1)->currentMove) ? to_sq((ss-1)->currentMove) : SQ_NONE;
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
                                       &thisThread->captureHistory,
                                       contHist,