The Anji bridge at Zhao County, usually called Zhaozhou Bridge, crosses the Xiao River on a single segmental stone arch. Its date is given as 605, in the Sui dynasty, and its designer as Li Chun. The innovation is in the shoulders: instead of filling the space between the arch and the roadway with solid masonry, the builders opened four small arches on each side, reducing weight and letting flood water pass. The bridge is on China's tentative World Heritage list, not among the inscribed properties.
Li Chun's stone bridge over the Xiao River has stood since the Sui dynasty, its shallow arch held by twenty-eight curved ribs and pierced at both shoulders by small flood arches. The span is still walked across, and its repairs, its rediscovery in the 1930s and its place on China's tentative World Heritage list are part of the story.