--- a/src/chess/rules.c	Thu May 28 13:58:24 2026 +0200
+++ b/src/chess/rules.c	Sun Jun 07 14:55:20 2026 +0200
@@ -922,3 +922,8 @@
         return snprintf(str, 6, "%02u:%02u", minutes, seconds);
     }
 }
+
+bool check_threefold_repetition(GameState *gamestate) {
+    // TODO: implement threefold repetition detection
+    return false;
+}