diff --git a/src/board.rs b/src/board.rs
index 4476012..b792297 100644
--- a/src/board.rs
+++ b/src/board.rs
@@ -557,7 +557,7 @@ impl Role {
 
     #[inline]
     pub(crate) unsafe fn transmute(i: u8) -> Self {
-        debug_assert!(i > 0 && i <= 6, "got {i}");
+        debug_assert!(i >= 1 && i < 7);
         unsafe { std::mem::transmute(i) }
     }
 }