What is the reason that the weapons of the Terracotta Army in the tomb of Qin Shi Huang have been perfectly preserved, shiny, and sharp after being buried for over two millennia?
More than 8,000 life-sized terracotta warrior figures were discovered in the tomb of Emperor Qin Shi Huang in Xi’an, China, in 1974.
However, it wasn’t until nearly three decades later that researchers discovered the weapons of the Terracotta Army are real, not replicas. Furthermore, these weapons are intricately crafted, with bows and arrows strong enough to pierce armor. Among them, arrowheads are the most commonly collected weapons by archaeologists. They are grouped into bundles of 100, representing the number of arrows in a quiver of an archer.
Each bow and arrow consists of a triangular arrowhead resembling a pyramid, a shaft that helps attach the arrow to a bamboo or wooden frame, and a feather attached to the tail. The metal components of the bow and arrow (the arrowhead and shaft) are the only parts that remain intact.
However, what is surprising is that these weapons have been preserved in remarkably good condition, with their surfaces still shiny and sharp after being buried for over two millennia.
The weapons of the Terracotta Army in the tomb of Qin Shi Huang are coated with chrome. (Illustrative photo)
A newly published study by a group of international scientists has answered this puzzling question: ancient Chinese artisans used a surprisingly advanced preservation method, employing chromium metal.
The weapons, including mirrors, spears, and polearms, have been preserved almost perfectly due to a coincidence—the combination of favorable soil conditions in the burial chamber and high tin content in the bronze metal. Scientists assert that the chromium found on the surfaces of the bronze weapons originated from a chromium-rich lacquer layer that artisans of the time applied to the terracotta figures and weapon components. They had no intention of using chromium for preservation purposes.
Chromium plating, a technology discovered in the early 20th century, is used to treat metals to prevent corrosion. The metal is immersed in a solution containing chromium salts. A layer of chromium oxide is deposited on the metal surface, creating a rust-resistant barrier.
Martinón-Torres, a participant in the research team from University College London in collaboration with the Terracotta Army Museum, stated: “Essentially, we demonstrate that the weapons of the Terracotta Army show an excellent state of preservation, but currently, there is no evidence suggesting this is anything other than a result of coincidence.”
Marcos Martinón-Torres, an archaeologist from the University of Cambridge and the lead researcher of the study published in Scientific Reports, mentioned: “The lacquer was applied to the Terracotta Army as a primer before they were painted in various colors, and we believe it was also applied to the wooden parts that have since decayed, such as the handles and shafts.”
Moreover, the bows and arrows found in the tomb of Qin Shi Huang are crafted with a level of sophistication that predates their time by two millennia.
