河西と代北 --九世紀前半の唐北邊藩鎭と遊牧兵--

Abstract

The Hexi 河西 (around the Ordos) and the Daibei 代北 areas in the northern peripheral belt of China during the Tang dynasty were the cradles of nomadic governments established in Northern China in the 10th century, such as those of the Tangut 党項 and Shatuo 沙陀 tribes. Various conditions in those areas during the latter half of the Tang dynasty directly caused these nomadic groups to gain power. The historical circumstances that caused these nomads to extend their influence to these areas have mainly been explained from the perspective of the study of their own history. However, the Tang dynasty must have had reasons for accepting the nomadic groups. Furthermore, altered circumstances accompanying this acceptance and antipathy to it must also have existed. Therefore, this paper examines the background of the local Tang military deployed in its northern peripheral territory and its acceptance of nomadic troops as well as the regional correlation between Hexi and Daibei under Tang policies regarding the northern peripheral territory by examining the Tangut uprising and its suppression by Tang forces during the first half of 9th century. The first section clarifies the previously obscure deployment of the Tang forces and their composition in the suppression of the Tangut during the Xuanzong 宣宗 era by means of analysis of the new Wang Zai 王宰 epitaph. The core of the Tang forces were not military authorities of Jingxi-Jingbei 京西京北 districts where the Tangut revolt took place, but those of the Hedong 河東 district and some nomadic groups from Daibei, such as the Shatuo who served under the Hedong corps. The second section considers the problems that occurred among the military authorities in the northern peripheral territory, especially those of Jingxi-Jingbei districts, at that time. The military governors there had committed various injustices ; for example, they had exploited Tangut people under their rule and the guanjian 官健, the regular soldiers of their armies. They had embezzled public funds by cutting the number of guanjian. That had also caused the hollowing-out of military strength in strategic points at those districts due to lack of guanjian. These problems were the reason for the Tangut uprising as well as the composition of the Tang military forces mentioned above. The third section examines the Tang central governmentʼs ideal for the northern peripheral territory and the reality there. Behind the hollowing-out of strategic military points in the northern peripheral territory was the military governors active incorporation of nomadic troops. They placed much store particularly in the nomadic groups of Daibei. On the other hand, the Tang central government denounced those military governors who committed injustices. However, it could not in fact keep them under strict control because they had built up close ties with the eunuchs. Therefore the Tang dynasty could not help but depend on the military power of nomadic troops for defense. The nomadic groups of Daibei had substantially controlled Tangut groups based in Hexi since the Wenzong 文宗 era, and they had continued to be the central corps of the Tang military forces in the suppression of Tangut during the Xuanzong era. Such acceptance of nomadic troops required a commensurate cost. It appears that the injustices by the military governors that were related to the cost of keeping those nomadic troops and at the same time the hollowing-out of troops at strategic points both facilitated the entry of the nomadic troops into the Tang military organization.