Communication with the plains of the Oxus and with Balkh (by the lower reaches of the Balkh Ab) is easy and frequent, but there never could have been a khafila road over the rugged plateau land and mountains which divide it from the basin of the Helmund. From time immemorial efforts have been made to reach Kabul by the direct route from Herat which is indicated by the remarkable lie of the Hari Rud valley. It was never recognized as a trade route, although military expeditions have passed that way; and it has always presented a geographical problem of great interest. From Herat eastwards, past Obeh as far as Daolatyar, there is no great difficulty to be overcome by the traveller, although the route diverges from the main valley for a space. Between Daolatyar and the head of Sar-i-jangal stream (which is the source and easternmost affluent of the Hari Rud) the valley is well populated and well cultivated, with abundant pasturage on the hills. But the winter here is severe. From the middle of November to the middle of February snow closes all the roads, and even after its disappearance the deep clayey tracks are impassable even for foot travellers. In the neighbourhood of a small fort called Kila Sofarak, about 40 miles from Daolatyar, there is a parting of the ways. Over the water-parting at the head of the stream by the Bakkak Pass a route leads into the Yakulang valley, a continuation of the Band-i-Amir, or river of Balkh, which, in the course of its passage through the gorges of the mountains, here forms a series of natural aqueducts uniting seven narrow and deep lakes. Inexpressibly wild and impressive is the character of the scenery surrounding those deep-set lakes in the depths of the Afghan hills. Near the lakes are the ruins of two important towns or fortresses, Chahilburj, and Khana Yahudi. On a high rock between them are the ruins of Shahr-i-Babar the capital of kings who ruled over a country most of which must have been included in the Hazara highlands, and was probably more or less conterminous with the Bamian of Idrisi. Between the Yakulang and the Bamian valley is a high flat watershed. Looking north-west a vast broken plateau, wrinkled and corrugated by minor ranges, and scored by deep valleys and ravines, fills up the whole space from the mountains standing about the source of the Murghab and Hari Rud to the Kunduz River of Badakshan. So little is this part of modern Afghanistan known, that it may be as well to give a short description of the existing lines of communication connecting the Oxus plains and Herat with Bamian and Kabul, before attempting to follow out their mediæval adaptation to commercial intercourse.