As Daishi and Shoshi, who were engaged in the practical business in Benkankyoku, were required to have a special skill of Sando and knowledge of practices in drawing up official documents, a sense of solidarity was formed among them; therefore, Sadaishijoshu which was the head of Daishi and Shoshi became a leader of Benkankyoku, presiding over Daishi and Shoshi.
弁官局で実際に実務を運営したのは大少史であり、特殊技能である算道、文書作成の慣行に関する知識が求められることから、専門職として一体意識が醸成され、大少史の筆頭である左大史上首が大少史を統括する弁官局の主催者となった。