Since it first opened to the public in 1974, Xi’an’s terracotta warrior museum has seen three large scale excavations. The archaeological work has become more precise and sophisticated in terms of the tools used.

Yang Siwa joined the excavation team in 1974. His memories of the dig are still fresh.

Yang Siwa says, "At the very beginning, we used shovels, pickaxes. And when we reached the bottom, archaeologists from around the country brought us some smaller tools."

The first excavation covered an area of 2,000 square meters. Yang Siwa and his colleagues spent five years digging out more than one thousand figurines, 32 clay horses and 8 chariots. The underground army surprised the world with its scale. As the excavation developed, the tools began to change.

Yang says, "We don’t use any big tools now. In the past we used lorries to carry away soil. Now we clear it all by hand, so it is very slow."

In 1985, the second excavation began and it also covered an area of 2,000 square meters. But the excavation was suspended due to technical issues and to protect the relics. In 2009, the third excavation began, covering 200 square meters.

Shen Maosheng, director of 3rd excavation team says, "We are using more precise tools this time, especially when it comes es to the surface of the relics. We will use small brushes, small prods and scalpels. The change in the tools is to protect the relics."

The change of tools reflects the advancement in archaeological ideology and technology. At the excavation site, protecting and unearthing the relics go hand in hand.

Though it slows down the excavation, it doesn’t stop the number of finds. More than 120 items have been found this time, but archaeologists also found signs of fire and flooding as well as a first lacquer shield, war drum and a complete set of weapons. All these signs provide clues to help uncover the mysteries of the terracotta warriors.