diff --git a/assignment1-18/chessboard.c b/assignment1-18/chessboard.c
index 2d348e8..dfac173 100644
--- a/assignment1-18/chessboard.c
+++ b/assignment1-18/chessboard.c
@@ -331,13 +331,19 @@ enum mstatus move(
         return INVALID;
     }
 
+    bool check_before_move = player_checks(cb, p == WHITE ? BLACK : WHITE);
     bool can = can_move(cb, p, from_row, from_col, to_row, to_col);
 
     if (!can) {
         return INVALID;
     } else {
+        // FIXME: check if move is allowed in check state
         cb_move(cb, from_row, from_col, to_row, to_col);
         if (player_checks(cb, p)) {
+            if (check_before_move) {
+                DEBUG("move: move does not end check state, invalid");
+                return INVALID;
+            }
             // TODO: check checkmate
             return CHECK;
         } else {