Several trade routes have traditionally converged on Leh, from all four directions. The most direct route was the one the modern highway follows from the Punjab via Mandi, the Kulu valley, over the Rohtang Pass, through Lahaul and on to the Indus Valley, and then downriver to Leh. The route from Srinagar was roughly the same as the road that today crosses the Zoji La (pass) to Kargil, and then up the Indus Valley to Leh. From Baltistan there were two difficult routes: the main on ran up the Shyok Valley from the Indus, over a pass and then down the Hanu River to the Indus again below Khalsi (Khalatse). The other ran from Skardu straight up the Indus to Kargil and on to Leh. Then, there were both the summer and winter routes from Leh to Yarkand via the Karakoram Pass and Xaidulla. Finally, there were a couple of possible routes from Leh to Lhasa.