This valley is bounded on the east by the mountain country of the Lolos, which extends north nearly to Yachau (_supra_, pp. 45, 48, 60), and which, owing to the fierce intractable character of the race, forms throughout its whole length an impenetrable barrier between East and West. [The Rev. Gray Owen, of Ch’êng-tu, wrote (_Jour. China B. R. A. S._ xxviii. 1893–1894, p. 59): “The only great trade route infested by brigands is that from Ya-chau to Ning-yuan fu, where Lo-lo brigands are numerous, especially in the autumn. Last year I heard of a convoy of 18 mules with Shen-si goods on the above-mentioned road captured by these brigands, muleteers and all taken inside the Lo-lo country. It is very seldom that captives get out of Lo-lo-dom, because the ransom asked is too high, and the Chinese officials are not gallant enough to buy out their unfortunate countrymen. The Lo-los hold thousands of Chinese in slavery; and more are added yearly to the number.”—H. C.] Two routes run from Ch’êng-tu fu to Yun-nan; these fork at Ya-chau and thenceforward are entirely separated by this barrier. To the east of it is the route which descends the Min River to Siu-chau, and then passes by Chao-tong and Tong-chuan to Yun-nan fu: to the west of the barrier is a route leading through Kien-ch’ang to Ta-li fu, but throwing off a branch from Ning-yuan southward in the direction of Yun-nan fu. This road from Ch’êng-tu fu to Ta-li by Ya-chau and Ning-yuan appears to be that by which the greater part of the goods for Bhamó and Ava used to travel before the recent Mahomedan rebellion; it is almost certainly the road by which Kúblái, in 1253, during the reign of his brother Mangku Kaan, advanced to the conquest of Ta-li, then the head of an independent kingdom in Western Yun-nan. As far as Ts’ing-k’i hien, 3 marches beyond Ya-chau, this route coincides with the great Tibet road by Ta-t’sien lu and Bathang to L’hása, and then it diverges to the left.