Yansanggou Xing Bridge was the first bridge crossed by Mao Zedong when he entered Sichuan during the Red Army's Four Crossings of the Chishui River in the Long March. As he crossed the bridge, Mao said, "I have finally set foot on the land of Sichuan!"

Located in Sunjiaba, Gulin County, the bridge was erected during the Qing Dynasty (1644-1911) and served as a major thoroughfare connecting Sichuan and Guizhou provinces. Well preserved, the bridge is 6 meters long, 1.3 meters wide and 5 meters high. Its load-bearing structure consists of three timbers, each measuring 5 meters long, 0.25 meters wide and 0.4 meters thick. The bridge deck is paved with flagstones, with no railings or decorative carvings. 

Although small in size, the bridge was crossed by tens of thousands of troops from the main force of the Central Red Army, witnessed the beginning of the Four Crossings of the Chishui River.