Since 2015, an archaeological team started to carry out studies on the five sacrificial sites. Archaeologists have found four sacrificial sites in Baoji and excavated three of them, namely Xuechi, Wushan and Xiazhan, and suggest that they were all constituent parts of yongwuzhi.

The Xiazhan site is 21.8 kilometers from Yongcheng city ruins, 35 km from the Xuechi site, and 59 km from the Wushan dig.

Some chariot pits at Xiazhan are similar to those from the Xuechi and Wushan sites, says You.

"With the establishment of the Qin Dynasty, yongwuzhi upgraded from the sacrificial sites of a vassal state to places to worship heaven as a country, showing the development of China's traditional ritual culture," says You.

He adds that the custom was inherited by the Western Han Dynasty later.

When scholars conduct archaeological studies on settlement sites or city ruins of the Qin and Han dynasties, capitals, tombs and sacrificial sites are the three major elements they pay attention to.

That means the importance of sacrificial sites is not second to capitals or tombs, says Jiao Nanfeng, a researcher at the Shaanxi Academy of Archaeology.

Most of the sacrificial sites of the Qin and Western Han dynasties recorded in historical literature have been found, forming a complete sacrificial system of that time, Jiao says.