Choku is the words of the emperor or a document that directly conveys the emperor's order. It is called Chokusho when the emperor's order is in document format. It was mainly used to convey the emperor's intention for a specific person and organization. Additionally, it is called Ordinance when the emperor's order is in oral format.
After seeking its origin through "Nihon Shoki" and other history books, it is found that Kinsekibun (words written on metal or stones) is used at the epitaph of Funeno Ogo, who was reburied in the Emperor Tenmu era, saying Funeno Ogo is granted the post by the Choku of the Emperor Jomei.
After the Taiho Ritsuryo (Taiho Code) was established, it mainly meant the Chokusho such as Chokushi based on Kushiki-ryo (law on state documentary forms in the Yoro Code). In addition, in the Nara period 764, Chokushi-sho (Bureau of Edicts), which was in charge of the implementation of Choku and Chokusho as well as the supply goods for the emperor and the imperial court, was set. However, it was abolished together with Zogusho (Ministry of Making and Mending Palaces) during the public administration restructure in 782.