Shiki was an organization to take charge of clerical work along with Ryo (ritsuryo system) and Tsukasa (also known as Shi) and to rule special areas (like Kyoto), mainly under the ministries (two ministries of Nakatsukasasho and Kunaisho).
職は寮(律令制)や司と共に主に省（中務省・宮内省の二省）などのもとで事務を行う組織､また特別地域（京など）を統治する組織である。