Piāntóuguān

Piantou Pass guards the rugged northwestern approaches to Shanxi, where mountain ridges lead west towards the Yellow River. Its name is traditionally linked to the uneven ground of the pass, high in the east and low in the west. The Ming made it a major northern frontier stronghold: in 1429 the regional commander moved his headquarters here, and the pass was enlarged in the decades that followed.

The defences grew into several overlapping lines of walls and beacon towers. In 1515 an additional wall was built south of the pass along the hills, and in 1575 the Ming authorised further towers and repairs along the frontier. These works guarded an exposed border while controlled markets provided places for exchange with communities beyond it.