As the word "shogun," its commander-in-chief, was first mentioned in 729, it is assumed that an institution equivalent to the Chinju-fu was established in some area in Togoku (the eastern part of Japan, particularly the Kanto region) in the early Nara period.
その長官である将軍の名が729年に初めて見えることから、奈良時代前半には鎮守府相当の機関が東国のいずれかの地に設置されたものと推測される。