Zhuge Liang's Northern Expeditions - Geography

Geography

Zhuge Liang's plan called for a march north from Hanzhong, the main population center in northern Yi Province. In the third century, the region of Hanzhong was a sparsely populated area surrounded by wild virgin forest. Its importance lay in its strategic placement in a long and fertile plain along the Han River, between two massive mountain ranges, the Qin in the north and the Micang in the south. It was the major administrative center of the mountainous frontier district between the rich Red Basin (Sichuan Plain) in the south and the Wei River valley in the north. The area also afforded access to the dry northwest, and the Gansu panhandle.

Geographically, the rugged barrier of the Qin Mountains provided the greatest obstacle to Chang'an. The mountain range consists of a series of parallel ridges, all running slightly south of east, separated by a maze of ramifying valleys whose canyon walls often rise sheer above the valley streams. As a result of local dislocations from earthquakes, the topographical features are extremely complicated. Access from the south was limited to a few mountain routes called the gallery roads. These crossed major passes and were remarkable for their engineering skill and ingenuity. The oldest of these was to the northwest of Hanzhong, and which crossed the San Pass. The Lianyun "Linked Cloud" Road was constructed there to take carriage traffic during the Qin Dynasty in the third century BCE. Following the Jialing Valley, the route emerges in the north where the Wei River widens considerably, near the city of Chencang. Another important route was the Baoye route, which transverses the Yegu Pass and ends south of Mei. A few more minor and difficult routes lay to the east, notably the Ziwu, which leads directly to the south of Chang'an.