It was known that the Kafirs occupied the crest of the Hindu Kush eastwards of the Khawak, but how far they extended north of the main watershed was not ascertainable. The southern limits of Badakhshan became definite again at the Dorah Pass. The Dorah connects Zebak and Ishkashim at the elbow, or bend, of the Oxus with the Lutku valley leading to Chitral. From the Dorah eastwards the crest of the Hindu Kush again became the boundary until it effects a junction with the Muztagh and Sarikol ranges, which shut off China from Russia and India. Skirting round the head of the Tagdumbash Pamir, it finally merged into the Pamir Mountains boundary, and turned westwards, following the course of the Oxus, to the junction of that river and the Khanabad (Kunduz).