--- a/src/chess/rules.h	Fri Jul 24 12:42:57 2026 +0200
+++ b/src/chess/rules.h	Fri Jul 24 12:44:42 2026 +0200
@@ -36,7 +36,7 @@
 #define VALID_MOVE_SYNTAX      0
 #define VALID_MOVE_SEMANTICS   0 /* use same code for a success */
 #define INVALID_MOVE_SYNTAX    1
-#define INVALID_POSITION       2
+#define PIECE_NOT_FOUND        2
 #define AMBIGUOUS_MOVE         3
 #define NEED_PROMOTION         4
 #define PIECE_PINNED           5