The only thing apparent at present was the Gishiki (Book) called "Engi Gishiki" during the late Heian period which might have been compiled or the contents of which might have originated during the Engi era and were highly regarded as authority.
従って現時点で明らかであるのは、平安時代の後期には延喜年間に編纂あるいは記録に由来を持つ『延喜儀式』という儀式（書物）が存在して、先例として重んじられていたということである。