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『東洋文庫所蔵』貴重書デジタルアーカイブ

58o   THE TUN-HUANG OASIS AND ITS NORTHERN LIMES [Chap. XV

forms the easiest and nearest approach from China to the Tarim Basin. From the place where this important river, fed by the glaciers and permanent snows of the Central Nan-shan, breaks through the last outer range and makes its great bend to the west, it runs almost due east to west for a direct distance of over 200 miles. Throughout open, as seen in Maps Nos. 74, 78, 81, 83, 85, this lower Su-lo Ho Basin offers itself as the natural continuation westwards of the great highway which starts from Lan-chou, the capital of Kan-su, and the upper Huang Ho. This route skirts the northern slopes of the Nan-shan and passes through a succession of fertile tracts that contain the big towns of Liang-chou, Kan-chou, and Su-chou, and an almost unbroken chain of smaller settlements. Nor are such settlements wanting on that section of the great China-Turkestan trade route, between Su-chou and Yü-mên-hsien, where it crosses by a series of broad plateaus the easy watershed dividing the drainage areas of the Pei-ta Ho, or Su-chou River, and the Su-lo Ho.5

No other line of communication can ever have offered such facilities for intercourse between China and Eastern Turkestan as the route along the submontane belt between the Huang Ho and Su-lo Ho which has just been briefly outlined. For large movements of troops or trade convoys it is, in fact, the only practicable route. To the south extend the snowy ranges of the Nan-shan and the forbidding high plateaus of northernmost Tibet, in the Koko-nôr and Tsaidam regions. On the north, that long but narrow belt .of cultivable ground is bordered by the deserts and almost equally barren hills of southernmost Mongolia, where no permanent habitations or cultivated areas could be found for distances requiring months of caravan journey. It is a necessary consequence of these physical facts that, from the earliest period of Chinese expansion westwards, the assertion of the empire's power in Central Asia has depended upon the safe possession of this great natural high road.

This is very clearly brought out by the passage of the Former Han Annals which records the first great move of Chinese forward policy ' under the Emperor Wu-ti. It tells us that, after the defeat of the Huns in 121 B. c., which cleared them from the territories adjoining the Nan-shan, ` the region of Chiu-ch`üan (i. e. Su-chou) was first established, and afterwards gradually the people were removed in to fill it. He also divided the three territories of Wu-wei (the present Liang-chou), Chang-yeh (now Kan-chou), and Tun-huang into four regions, for which he made two barriers.' 6 When almost exactly two thousand years later the Chinese imperial forces, after the crushing of the great Tai-ping rebellion in the south, were preparing for the reconquest of Chinese Turkestan, then under Yakub Beg's rule, the course of operations here described had to be repeated closely, mutatis mutandis. The Tungan rebels were driven off the fertile belt at the north foot of the Nan-shan, the great ` Imperial Road ' leading through it secured by a line of cantonments and watch-stations, and the almost 'depopulated oases recolonized from China before the Chinese forces under the famous generals Liu Chin-tang and Tso Tsung-tang could set out in 1877 victoriously to win back the lost ` New Dominions'.'

As soon as the lower Su-lo Ho basin is gained, two main lines of advance are open into the lands which, now once more, form China's Central-Asian foothold. One leads via Tun-huang down to the terminal basin of the Su-lo Ho, and thence in ancient- times had its most direct and important continuation westwards, as we have seen,. down the Besh-toghrak valley to the dried-up Lop sea-bed and to Lou-lan. The other, equally straight, now turns off from An-hsi, the old

Western highway of Kan-su.

Road along N. foot of Nan-shan.

• See Maps Nos. 85, 86, 88 ; cf. also Desert Cathay, ii. P. 337.

• Cf. Wylie, Notes on the Western Regions," Anthrop. Inst., x. p. 22 ; also Chavannes, Documents, p. v. The two ' barriers' in the ' Wall' which the text refers to are the huan

of Yil-mên, the ' Jade Gate ', and Yang, about which see below, pp. 62o sqq. ; chap. xrx.

7 For this interesting modern chapter in the history of China's relations with Central Asia, cf. Boulger, The History of China, iii. pp. 732-744.

Road to west opened by Chinese,

121 B.C.

Main lines of advance from Su-lo Ho.