国立情報学研究所 - ディジタル・シルクロード・プロジェクト
『東洋文庫所蔵』貴重書デジタルアーカイブ

Sec. iv]   THE POSITION OF THE `YANG BARRIER   621

Moreover, the archaeological evidence which I gathered at the site fully accords with the fact that Shou-ch`ang hsien is spoken of as ` extinct ' in the Huan yü chi, a Chinese text published between A.D. 976 and 983, which Dr. Giles quotes in continuation of the above extract. Accepting then the identity of the extant ruined town at Nan-hu with the Shou-ch`ang hsien of the Old T'ang Annals, we are justified in concluding that the Yang barrier must have stood close to the western edge of the present Nan-hu oasis.

If we test that location by the reference which the passage quoted by M. Chavannes from- the Old Tang Annals makes to the position of the Yü-mên barrier, we find it in full agreement with topographical and archaeological facts. The ` Jade Gate ' is there placed i i8 li to the north-west of Shou-ch`ang hsien, and a reference to the map shows that the ruined station T. xiv (Map No. 74. D. 3), which conclusive archaeological and documentary evidence proves to mark the position of the ` Jade Gate' during the period while the Limes was occupied in Han times, lies almost exactly to the north-west of the ruined town of Nan=hu, and at a direct distance of about thirty-six miles. The discoveries which enable us to fix the position of the ` Jade Gate ' on the ancient Limes will be found discussed below.4a There, too, will be the right place to explain in detail how striking a confirmation for the location of the Yang barrier at Nan-hu was furnished by the discovery of an ancient secondary line of wall which leaves the main Limes at T. xiv and strikes across the desert to the south-east, exactly in the direction of the terminal area of Nan-hu cultivation as marked by the towers T. xvIII. a, b (Map No. 78. A. 4).5 In the light of what we now know as to the position of the Yang barrier, it appears to me highly probable that the purpose of this secondary wall with its watch-towers was to assure the safety of the line of communication linking up the two important ` barriers ', or frontier stations, of Yang and Yti-mên.

The close connexion between these two frontier stations and their nearness to each other is also clearly brought out by the references made to them in the Former Han Annals, though by themselves, and without the aid df archaeological investigation on the spot, these references would not allow us to fix the positions with exactness. The ` Jade Gate ' and the ` Yang barrier ' are mentioned together, in Chapter XCVI of the Ch`ien Han shu, as the starting-points for the two roads to the Western Regions which we have already had occasion to discuss.° The fact that both are stated to be some 300 li distant from the P`u-ch`ang Lake, or Lop-nor, implies, as Dr. L. Giles has rightly recognized; that the two were at no great distance from each other.? No direct topographical indication is furnished by the statement made in the same chapter that the two ` barriers ' were established at the time when, soon after the conquest of westernmost Kan-su in I 2I B. C• under the Emperor Wu-ti, the newly-won territories were colonized and divided into four commands (chien) including Tun-huang.8 But another passage, in Chapter XXVIII of the Chien Han shu, supplies the important information ` that the Yang and Yii-mên barriers were both in Lung-lo hsien',' i. e., as we have proved above, in the Nan-hu tract.

The Han Annals, as far as they are accessible in translation, do not contain any explicit statement about the relative position of the two frontier stations within this tract. But fortunately there is a passage in them which, if it is read with proper attention to the geographical facts established by our surveys, makes it perfectly clear that the Yang barrier must have been situated in the south,

Location of Yang barrier' at Nan-hu.

References to Yang kuan and Yit-men in Former Han Annals.

Identity of

Yang kuan

with Nan-hu proved.

4a See chap. xix. sec. i—iii.

6 See below, chap. xix. sec. iii. In Map No. 74. D. 3 the secondary line of wall is wrongly shown as running south from T. xiv. Its continuation to the south-east was duly traced by me in 1914 for some distance. In Pl. 33 the direction of this wall is indicated somewhat more correctly.

6 See Wylie, J. Anihrop. Insl., x. p. 2 1 ; cf. above,

pp. 333 sq., 345, 4r8, note rr.

• Cf. Giles, Tun Huang Lu, J.R.A.S., 1914, p. 715.

• Cf. Wylie, loc. cil., x. p. 22 ; Chavannes, Documents, pp. v sq., note 5, where the dates indicated by other passages of the Annals for these measures are critically examined.

9 Cf. Giles, JR.A.S., 1914, p. 715.