Suoyang City (), also called Kuyu (), is a ruined Silk Road city in Guazhou County of Gansu Province in northwestern China. First established as Ming'an County in 111 BC by Emperor Wu of Han, the city was relocated and rebuilt at the current site in 295 AD by Emperor Hui of the Western Jin dynasty. As the capital of Jinchang Commandery (later Guazhou Prefecture), the city prospered during the Tang and Western Xia dynasties. It was an important administrative, economic, and cultural center of the Hexi Corridor for over a millennium, with an estimated peak population of 50,000. It was destroyed and abandoned in the 16th century, after the Ming dynasty came under attack by Mansur Khan of Moghulistan.
The city ruins comprise the inner city, the outer city, and several yangmacheng (fortified animal enclosures used as fortresses in wartime). Outside the city walls, the broader archaeological park includes the original site of Ming'an County, more than 2,000 tombs, and the remains of an extensive irrigation system with over of canals. The archaeological park also encompasses a number of Buddhist sites, including the Ta'er Temple, the Eastern Thousand Buddha Caves, Jianquanzi Caves (), and Hanxia Caves ().
Suoyang City is listed as a Major National Historical and Cultural Site of China (No. 4-50). In 2014, it was inscribed on UNESCO's list of World Heritage Sites as part of Silk Roads: the Routes Network of Chang'an-Tianshan Corridor.
Location
Suoyang City is located in the Gobi Desert, southeast of modern Suoyangcheng Town, Guazhou County, in Gansu Province of Northwestern China. It occupies the site of an ancient oasis in the Hexi Corridor, at an altitude of above sea level. During its existence of about 1,700 years, the city was a major political, military, economic and cultural center on the Silk Road, between Dunhuang (Shazhou) to the west and Jiuquan (Suzhou) to the east.
City ruins
The walled city comprises an inner city, an outer city, and several yangmacheng fortresses in between.
Inner city
The inner city is in the shape of an irregular rectangle measuring in area. Its four walls measure (east), (west), (south), and (north). The bases of the rammed earth walls are wide, and the remaining walls are 9 to 12.5 m tall.
Two main streets run through the western and northern gates, respectively, with many smaller streets and alleys branching from them. A partition wall divides the inner city into two sections: the larger western city and the smaller eastern city. Many house remains and thick layers of charcoal have been found in the western city, while the eastern city has few remains. It is likely that the eastern city housed the government buildings and residences of high-ranking officials, while the general populace lived in the western city. In the northwest corner of the inner city, an tall adobe watchtower remains standing.
Outer city
The outer city is also an irregular rectangle. Its walls measure in the east, in the west, and in the north. The south wall is broken into two parts: a eastern section, and a western one. The bases of the outer city walls are between wide, and the remaining walls are between tall. The northern part of the outer city is divided from the rest by an internal wall north of the inner city.
The outer city is believed to be the largest extent of Suoyang at its peak during the Tang dynasty. It was destroyed by floods coming from the mountains in the south, which breached the southern wall and cut it into two sections. Most buildings in the city were destroyed or damaged, the remains of which have been found in the outer city, covered by a thick layer of flood sediments. The outer city and the outer walls were not rebuilt or repaired after the destruction.
Yangmacheng
Between the outer and inner cities are several fortresses known as yangmacheng (literally "sheep-and-horse city"). A common feature of Tang dynasty cities, they were used as animal enclosures in peace time to keep humans and livestock apart as a disease-prevention measure, and as military fortresses in wartime. There are no signs that the ones at Suoyang were repaired or used after the Tang dynasty.