北周外交遣使小札

A Study of Appointment of Envoys in Western Wei/Northern Zhou

It is a tradition that regimes sent envoys mutually during the period of disunion. It's not just for diplomacy negotiations, but the way to collect political and military information about the other side. Since Northern Wei established the rule of appointing Sanjichangshi （散騎常侍） to be an envoy, both Southern Dynasty and Eastern Wei/Northern Qi continued practicing this rule. However, Northern Zhou was under Zhouguan（周官） structure, and the way to appoint envoys was very different. Examining the practical cases, Northern Zhou often nominated envoys according to their ability more than their political position. Yang Jian（楊荐） for Rouran, and Du Gao（杜杲） for Chen Dynasty were examples. On the other hand, Yuzheng （御正）, Yubo（御伯）, and Nayan（納言） were also sent on diplomatic missions frequently. Probably because Yuzheng was belonging to Zhongshu （中書） system and Yubo/Nayan was belonging to Menxia（門下） system, both of these two systems were in charge of the expression of emperor's opinions.