Military officers of border and Fortress During Han Dynasty Unearthed from “The Law of The Second Year” in Zhangjiashan Han Bamboo Slips and Documents in Northwestern Borders

The research is about two military officers during Han dynasty: military officers
of border（塞尉） and fortress（城尉）. According to “the law of the second year
（二年律令）, ” there were military officers of border and fortress of
commanderies(郡) , counties（縣）, roads（道） and shores along with yellow river
（河）in early Han. In early Han , Han was divided into areas directly controlled by
central government, and a number of semi-autonomous kingdoms（諸侯王國）. Owing
to the tension between central government and kingdoms, Han central government
thus arranged defense systems with a number of soldiers and officers not only in
borders between Han and barbarians but also in borders between Han and kingdoms.
After the rebellion of the seven kingdoms(七王之亂), Han central government took
back most powers from kingdoms. There was no reason to maintain a number of
military officers in borders between Han and Kingdoms. Consequently, in the rule of
Emperor Wu(武帝), military officers of border and fortress were only set in borders
between Han and barbarians, and those two officers were combined to army
commanders（郡都尉） who led soldiers to defend border lines of frontier
commaderies（邊郡）. Therefore, when scholars research those two military officers
based on documents in northwestern borders（邊塞漢簡）, they believed those two
officers were arranged only in frontier commanderies. However, in early Han, those
two officers were arranged in frontier and inner commanderies（邊郡、內郡） because
of tension between Han and kingdoms.