What is the origin of Gou Jian's sword? Why is it still as new after 2400 years?

1965, archaeologists excavated a 2400-year-old Chu tomb in Jingzhou, Hubei Province, with an unsheathed sword beside the owner's body. Everyone at the excavation site was shocked when the archaeologist pulled the sword out of its sheath. The bronze sword of 2400 years ago was radiant with cold light, complete as new. How can a bronze sword be buried underground for 2400 years without rusting? At present, the bronze weapons unearthed in the same period are rusty and the prototype is difficult to distinguish. What is the origin of this sword? It's amazing.

The eight-character inscription on the sword reveals the answer. Gou Jian, the King of Yue, is the protagonist of Zi Jian and Gou Jian, and one of the five tyrants in the Spring and Autumn Period. This sword turned out to be a legend of king. No wonder the exquisite craftsmanship has never been seen before. The body of the sword is inlaid with precious stones, and the head of the sword has 1 1 concentric circles, and the minimum distance is only 0.2 mm. In addition, the sword has not rusted for thousands of years, which even archaeologists are puzzled. Some people even suspect that this sword is a relic of alien civilization.

The researchers examined the composition of the sword body with instruments and found that Gou Jian's sword was made of copper-tin alloy, just like other bronzes. Can it be said that the reason why the Millennium is stainless is its storage environment? However, three other bronze swords were unearthed in this ancient tomb, but all of them were corroded to varying degrees. Only Gou Jian's sword can't even find a rust spot all over his body. Why?

The expert's eyes rested on the black lacquered scabbard of Gou Jian's sword. Raw lacquer has the functions of moisture resistance, high temperature resistance and corrosion resistance, and the black lacquer sheath becomes the first protective layer of Gou Jian's sword. The Jian Peijun sword has a second protective layer. The coffin where it is located is wrapped in layers of single coffins, and the white paste mud filled around it isolates the outside air from the inner chamber of the coffin, and the groundwater that permeates the whole tomb becomes the third protective layer. The three-layer protection constitutes a stable condition of completely isolating oxygen, which is the secret of Gou Jian's 2400 stainless steel.