The system of the dynasty state during the Heian period outsourced the Imperial Court's administrative organizations such as military affair (military art), accounting (calculation) and legal work (Myobo [law]) to the 'ie' (family) of the official for practical works who had succeeded various iegei (family's specialty) from a government official who was trained in the Ritsuryo-system organization.
軍事（武芸）や経理（算）、法務（明法）といった朝廷の行政機構を、律令制機構内で養成された官人から様々な家芸を継承する実務官人の「家」にアウトソーシングしていったのが平安時代の王朝国家体制であった。