Ceremonial turquoise article shaped like a dragon.[Photo provided to China Daily]

During the time of the Erlitou Site (3,750 to 3,550 years ago), in Luoyang, Henan province, China entered what is often called the age of dynasties, Wang said.

"Erlitou marked the time when the Central China plain began to widely influence the surrounding areas," he said. "It created a foundation for a united country with multiethnic groups."

Speaking of how to define "civilization", Zhao Hui, a professor at Peking University who is in charge of the project, said traditional criteria in Western academia, which emphasize the appearance of written characters and metallurgy, have not strictly been used in this project.

Liangzhu and several other early civilizations in China, however, are known for their highly developed techniques in making jade articles.

"Some characters of human development are common," Zhao said. "The difference also shows there are some unique characters in early Chinese civilization."

He said Chinese civilization also absorbed influences from other civilizations. Archaeological discoveries show wheat cultivation, breeding of cattle and sheep, and bronze-making technology in China originated in Western and Central Asia and were later adopted and acquired local characteristics.