A team of Chinese experts has started a new excavation project on the Terracotta Warriors site in Xi'an this year. The dig is taking place in Pit 2, where a unique green-faced Terracotta Warrior was unearthed in 1999.

Sixteen years after being unearthed, the paint on the face still remains. That depends on exploration and innovation of scientific and technological means of protection.

Thanks to more than 10 years of cooperation with Germany's Bavarian Administration of Cultural Heritage, Terracotta Warriors were able to be preserved in their originally painted colors. Experts of the two countries therefore figured out the layers of painting, composition of the painting material, process of drawing and the mechanism of discoloration.

China now uses wireless sensory networks, radio frequency tags , high-definition image processing , and intrusion detection in protecting those Terracotta Warriors, said Ren Xiayin, deputy director of restoration department of Qin Shi Huang Mausoleum Museum.

In addition, more than 20 Chinese experts have been to Germany for an exchange of experiences in protecting heritage and restoring historical artifacts, said HouNingbin, director of Qin Shi Huang Mausoleum Museum.