In Daijokancho written in 806 and carried on "Shinsho kyakuchoku fusho," they were treated as the same kind; it is presumed that they were considered to be the same in those days.
『新抄格勅符抄』に所収されている大同(日本)元年（806年）の太政官牒では一括して扱われ、この頃には両者が同一のものとみなされていたとみられている。