The Qing dynasty bidge at Luding, on the Tea Horse Road, Sichuan, China.

Immediately to the west of Erlangshan, the mountain that effectively divided the Han lands of Sichuan with their tea mountains from wilder territory, the Dadu River marks the beginning of Kham and the high grasslands. The Luding Bridge, built in 1705, became the official control point for the Qing government, where the yin quota tickets on the tea bales were checked. In 1935 this was the site of a battle in which the Red Army secured the important crossing.