The terraces are surrounded by moats. Archaeologists have excavated and studied part of a moat around No 1 terrace, and have worked out the huge labor required to build it.

"The moat is 20 meters wide and 10 meters deep. After excavation, the bottom and two sides were built up with three to four meters of rammed earth to avoid soil erosion. We believe there was really water flowing inside, or the rammed earth would not have been necessary. It can be regarded as part of a grand-scale water conservation project," says Han.

He mentions that to complete such moats, the labor required may be even more than that involved in the building of the F1 and the terraces. "The large-scale project required a great amount of manpower and material resources, and that must be realized through a powerful leader," Han says. "The presence of monarchy indicates the appearance of civilization."

According to Zhang Xiaoning, social division was very obvious. Around the site, by the side of Dongzhi plateau, there are cave dwellings that are thought to have been the homes of ordinary people, where daily-use pottery has been found that is much different from such items found in F2.