<論説>唐代青海東辺の諸城塞について : 『玉樹県志稿』の紹介を兼ねて

Abstract

唐帝国では、吐蕃(古代チベット王国) の東進を防ぐために、開元の初に隴右節度使を置き、青海湖東辺に若干の城塞を設置した。それらは湟水の流域に沿い、或は湟水に注ぐ支流葯水の流域に存在した。しかしその位置は、元和郡県図志・通典・新唐書地理志などに里数と共に明記されているにも拘らず、比定は不正確なままであった。ここでは近年発刊された玉樹県志稿の附録に記された諸城比定を手引きにそれらの位置を確定化する。その結果は、水経注に書かれた漢魏以来の城塞の位置が多く唐代のそれと一致し、唐代にはその戦線が一層前進せしめられたことが明かになった。而してそれらの城塞は、玄宗の開元時代に最も多く設置されて活動し、それによって唐の吐蕃封じ込め作戦は成功したのである。

T'ang Empire appointed a commander in chief of Lung-yu district 隴右節度使 and constructed some fortresses to the east of Köke najur 青海湖 for the purpose of preventing the eastward movement of T'u-fan 吐蕃 (Ancient Kingdom of Tibet) at the beginning of the Dynasty. Those fortresses were located along the Huang-shui River 湟水 and along its branches. Several old volumes such as Yuan-ho-chön-hsien-t'u-chih 元和郡県図志, T'ung-tien 通典, and Hsin-t'ung-shu, ti-li-chih 新唐書地理志 referred to them articulately, pointing their respective locations by the li 里. Nevertheless, the exact sites of them have never been definitively fixed as yet. The subject of this article is to determine the exact sites of those fortresses by the method of the historical comparison of places included in the Appendix of Yü-shu-hsien-chih-k'ao 玉樹県志稿 which was published lately. As the result of the analysis, the following was proved. First, many of the fortresses in the T'ang Period were built just on the very spots where the older ones to which Shui-ching-chu 水経注 referred had been located since the Han and Wei Period 漢魏. Secondly, the front against the enemy was further advanced in T'ang Period. Furthermore, most of those fortresses were built in the reign of Hsüan-tsung 玄宗, and they functioned effectively and successfully enough to prevent and enclose T'u-fan.