Shugokushi (Prisons Office) was one of the agencies that belonged to Gyobusho (Ministry of Justice) in ancient Japanese system of centralized governance.
Shugokushi administered two prison houses in Kyoto, carried out a sentence and watched the prisoners. Among officials of the Capital only Shugokushi staffed mononobe-cho instead of jikicho (factotum) who did odd jobs. The reason why there was such discrimination though these jobs weren't so different was that prison houses seemed to be the unclean place. The duty of mononobe, which was a section of tomobe (Servant of the Court, low-grade tech worker), was to administer mononobe-cho and to guard prison houses. Most of its duties were done by kebiishi (officials with judicial and police powers) and Shugokushi became titular in the Heian period. In addition, the position of Kami (director) of Shugokushi is said to have been avoided.
Kami (ranked Shorokuinojo [Senior Sixth Rank, Upper Grade]): one person
Jo (secretary) (ranked Jushichiinoge [Junior Seventh Rank, Lower Grade]): one person
Daireishi (ranked Daihatsuinojo [Greater Initial Rank, Upper Grade]): one person, and, Shoreishi (ranked Daihatsuinoge [Greater Initial Rank, Lower Grade]): one person
Shibu (low rank staff)
Mononobe : 40 people
Mononobe-cho : 400 people