The early Tang dynasty managed foreign tribes who surrendered to Tang by establishing the Zhou-xian (州縣) district system. In some cases, the chief of each tribe was appointed to the minister of the newly established district that represents his tribe. These districts appear basically identical to the ordinary Zhou system despite their differences to some degrees.
The Jimifuzhou system was devised to manage a large number of refugees occurred due to the fall of the East Turks at 630 C.E. The establishment of this system brought a remarkable transformation to Tang’s traditional policy for managing foreign tribes as it was distinguished from the former policy that assimilated them into the general (native) citizen of Tang.
There were clear boundaries between the jimi(fu)zhou districts governed by Frontier’s Government-generals and the ones by Protectorate-generals, which were placed outside the districts in charge of the Frontier’s Government-general. Those boundaries, referred to as bian(邊), sai(塞), guan(關), guojing(國境), and so on, were institutional; nevertheless, they did not indicate territorial borders. Territories of Tang should be understood by measure of the actual controlling power, and in that light, a considerable number of the jimifuzhou districts under the control of the Protectorate-generals should be considered to have belonged to the domain of Tang.