In those days, one century passed after the implementation of Ritsuryo system (a system of centralized government based on the ritsuryo code), and farmers who had been assumed as an equal class tended to be stratified.
当時は律令制の本格施行から1世紀が経過し、均等な階層として想定されていた百姓層の階層分化が進行しつつあった。