diff --git a/moo/lib/moo.c b/moo/lib/moo.c
index 58edd03..376570c 100644
--- a/moo/lib/moo.c
+++ b/moo/lib/moo.c
@@ -102,9 +102,7 @@ int moo_init (moo_t* moo, moo_mmgr_t* mmgr, moo_oow_t heapsz, const moo_vmprim_t
 	moo->option.dfl_symtab_size = MOO_DFL_SYMTAB_SIZE;
 	moo->option.dfl_sysdic_size = MOO_DFL_SYSDIC_SIZE;
 	moo->option.dfl_procstk_size = MOO_DFL_PROCSTK_SIZE;
-#if !defined(NDEBUG)
 	moo->option.karatsuba_cutoff = MOO_KARATSUBA_CUTOFF;
-#endif
 
 	moo->log.capa = MOO_ALIGN_POW2(1, MOO_LOG_CAPA_ALIGN); /* TODO: is this a good initial size? */
 	/* alloate the log buffer in advance though it may get reallocated
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 6d651e2..8a162b6 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -1183,10 +1183,8 @@ struct moo_t
 		moo_oow_t dfl_sysdic_size;
 		moo_oow_t dfl_procstk_size; 
 
-#if !defined(NDEBUG)
 		/* set automatically when trait is set */
-		int karatsuba_cutoff;
-#endif
+		int karatsuba_cutoff; /* used only if NDEBUG is not set */
 	} option;
 
 	moo_vmprim_t vmprim;