Introduction to the Erjiangcheng ruins: The Erjiangcheng ruins on Ziwu Ridge are located in Shanzhuang Township, Huachi County today. This ancient city wall is located on the top of the mountain and is a representative ancient city among many walled cities. The words "Dashun Chengguan" discovered during the investigation of the city's ruins confirmed that this was the city of Dashun built by Fan Zhongyan, the magistrate of Qingzhou during the Northern Song Dynasty, to resist the Western Xia Dynasty.