The discovery of large walled sites from the middle Changjiang River valley during the last six years has provided impetus for examining the development of complex societies. I have focused on the walled sites during the third millennium B.C.in the discussions about the origins of Chinese civilization. For that purpose we, have excavated Yinxiangcheng site, one of the medium-sized walled sites. Our team excavated in 1995-96 and simultaneously undertook archaeological surveys for the other walled sites.
We have investigated seven large sites with walls in the middle Changjiang River valley. It appears that these walled sites were constructed during the Qujialing Culture. There is an intriguing variation in the size of the walled enclosures. The site of Shijiahe is the largest walled site complex, now more than 40 settlements are known to have existed inside and outside the enclosed area. Except for some houses, storage pits and burials, the major find at the site is a ritual structure. Among the ritual objects the big-mouth zun beaker with incised symbols, which were typical of the Dawenkou Culture, is of the utmost significance. There can be no question that the Qujialing-Shijiahe Culture and the Dawenkou Culture made contact with each other directly, and that the Shijiahe site served as the ceremonial center and the central place for long distance exchanges within the regional political unit.