According to "Kushiki-ryo" (law on state documentary forms in the Yoro Code), Taifu referred to a government official of: Sanmi (Third Rank) or higher in Daijokan (Grand Council of State); Shii (Fourth Rank) or higher in Ryo (bureau); and Goi (Fifth Rank) or higher among Kokushi (provincial governors) who were lower than 国司国等級区分 (the grade classification of Kuni [provinces] and Kokushi [provincial governors]).
日本における大夫は、『公式令』により、太政官においては三位以上、寮においては四位以上、国司国等級区分以下の国司においては五位以上の官吏の称とされた。