Sec. iii] PAST THE KARLIK-TAGH AND BARKUL 539
settlements.' In addition to this pass, through which runs the high road between Hâmi and Barkul, there are others on either side, crossing the depression between the snowy portions of the range and likewise practicable for horsemen, except perhaps in the depth of winter.8
Geographical factors thus establish a strategic relation between Hâmi and the Barkul basin ; and it follows from this relation that the route which leads through Hâmi and provides the most direct and easiest line of access from the Kan-su marches to the tracts on either side of the Tien-shan, cannot be kept safely open for traffic and trade, unless the Barkul basin is also brought under effective control. All that we know from Chinese records about the history, both ancient and modern, of these two territories fully illustrates the nexus between them and its bearing upon the use of the .important desert route from the direction of An-hsi and Tun-huang.
SECTION IV.—HISTORICAL RELATIONS BETWEEN BARKUL AND HAMI
The evidence afforded by the Former Han Annals in respect of the historical nexus that geographical facts have established between Barkul and Hâmi is not less significant because it is negative. We know that during the period of nearly two centuries which followed the first expansion of Chinese trade and political influence towards the Tarim basin Under the Emperor Han Wu-ti from 121 B. c. onwards, the Hsiung-nu or Huns, though driven by the Chinese out of the passage land along the northern foot of the Nan-shan, yet maintained their power unbroken to the north of the Tien-shan. Thence they were able repeatedly to threaten, not only the Chinese control over the oases of the Tarim basin, but also the far-stretched line of communication which connected them through the Lop Desert with the westernmost marches of Kan-su ; it was to safeguard this line from their attacks that the Han Limes was pushed forward beyond Tun-huang.1
Throughout that period, which extended to the downfall of the Former Han dynasty soon after the beginning of the Christian era and for nearly fifty years after the succession of the Later Han dynasty in A.D. 25, Hâini and the route leading through it remained wholly outside Chinese domination and even outside the scope of Chinese military enterprise. It is for this reason that no account of Hâmi is to be found in the ` Notices of the Western Regions ' contained in the Former Han Annals, and that they are similarly silent about the region of Barkul. The latter must during all that time have been held by Hun tribes, and probably served as a main base for attacks against the Chinese border across the Pei-shan ranges south-eastwards. I have explained elsewhere how this ever-present threat of the Huns from across the easternmost Tien-shan determined the direction of the ` new northern route ', which the Chinese in A. D. 2 opened from the ancient ` Jade Gate ' in order to communicate with ` Posterior Chü-shih' or the territory around the present Guchen.2 To reach this ground, which, like Turfân immediately to the south, had passed early under their control, the route via Hâmi would undoubtedly have been the easiest. Yet Chinese administrative policy, always disposed to face physical difficulties rather than risks from hostile
7 I regret that I was unable either in 1907 or 1914 to visit the pass myself. But it was mapped on the former journey by R. B. Làl Singh, whose survey shows that the top of the pass lies on a perfectly open plateau offering no facilities for defence ; nor is there apparently any strong defensive position to be found lower down on the southern approach to the pass.
8 Of these passes the Kulluk-dawàn to the west seems higher, the Chagan-bulak-dawàn to the east about r,000 feet lower than the Barkul-dawàn. I may add here that there is a pass known as Belü-dawàn (not marked in the map)
leading due south of the Tur-köl across the Karlik-tâgh into the valley of Narin (Map No. 34. D. 2). It is shown in Mr. Carruthers' map with a height of close on 11,000 feet and appears to be practicable only during the summer and early autumn. Farther east the Karlik-tàgh can be crossed at any season by the route leading from Tâsh-bulak to Atürük via Tal.
1 Cf. Serindia, ii. pp. 724 sqq. ; Chavannes, Documents, pp. v. sqq.
2 Cf. Serindia, ii. pp. 705 sqq,