It is widely known that Qinshihuang, the first ruler of the Qin Dynasty (221-206 BC), built a great mausoleum in what is now Xi'an, Shaanxi province, with Terracotta Warriors believed to be safeguarding the tomb. Since no archaeological excavation has been carried out on the tomb, and there are no signs of it being successfully robbed, the well-preserved large-scale construction has aroused curiosity for generations.

Shiji, or Records of the Grand Historian, the foundation text of Chinese history dating back to the first century BC, records that a large amount of mercury was used to simulate "a hundred rivers and seas", and was set to flow mechanically in the underground palace of the tomb should it be breached. And archaeological and geological surveys have proved the abundant existence of mercury in the palace, suggesting the record is probably true.

But most people may not know the design is related to the marine concepts of the Qin people. In their eyes, the mysterious sea was related to celestial beings and even immortality. It was also an auspicious sign for a regime, according to Wang Zijin, a historian specializing in studies of the Qin and Han (206 BC-AD 220) dynasties.

Wang, professor at Northwest University and Renmin University of China, expresses this idea in his newly published book, The Spiritual World of Qin People, which explores the belief system of the Qin people based on historical literature and archaeological findings. The book was launched at a seminar in Beijing on June 14.