河西漢塞=Han dynasty garrisons in the Hexi region; 居延漢簡=Han dynasty wooden and bamboo slips from Juyan; 肩水金關漢簡=Han dynasty wooden and bamboo slips from Jianshuijinguan; 屯田=farming garrison; 治渠卒=soldiers in charge of waterworks
From the middle of the Western Han to the early Eastern Han, the empire had maintained the garrison system in the Hexi region in order to defend against the Huns. Han dynasty wooden and bamboo slips found in northwest China classified soldiers of the garrison system stationed in this region into categories such as garrison soldiers, farming soldiers, and soldiers in charge of rivers and canals. An examination of these Han dynasty records from Juyan and Jianshuijinguan as well as extant documents indicates that the traditional "hequ-zu(river-canal soldiers) " should actually be identified as " zhiqu-zu," a category of solider mainly engaged in the construction and maintenance of waterworks in farming areas.
