Diāomén

Diaomen lies in the mountains of western Sichuan, in the upper valley of the Qingyi River below Erlang Mountain, in what later became the Tianquan area west of Ya'an. Here the edge of the Sichuan basin gives way to steep forested ridges, narrow valleys and scattered settlements, and the route from Ya'an toward the Tibetan borderlands had to pass through the gorges. The name Diaomen means roughly the "blockhouse gate", and it recalls the stone towers and fortified passes that guarded this road.

The district was long a frontier. Western Han set up a county in this country in 111 BC, and under the Tang four military posts were placed here in the eighth century. In the Song and Mongol periods Diaomen was a fortified post on the road to the Tibetan lands, and the Yuan listed it among the districts under the command for the Tibetan borderlands. The name Tianquan first appears under the Yuan in a pacification office, and the Ming organised the area as the Tianquan Six Tribes Pacification Commission under local chieftains. Ya'an's tea-and-horse office at Diaomen traded Sichuan tea for Tibetan horses in the early Ming. The native chieftaincy lasted until the Qing abolished it in 1729 and created Tianquan Subprefecture.