Researchers have deciphered enigmatic recipes for metal-making contained in an ancient Chinese text, revealing unexpected complexity in the art at the time.
Six chemical formulas are given in a Chinese text from 300BC known as the Kaogong ji. The manuscript, known as The World’s Oldest Encyclopedia of Technologies, forms part of a detailed archive of early imperial rule, which archeologists have been trying to decode since the 1920s.
“The Kaogong ji may have been written by an administrator to assure the emperor that everything was under control. It is part of a manual for how to run the empire,” said Prof Mark Pollard, from the University of Oxford.
For 100 years, scholars have grappled with the meaning of two key components of the recipes: Jin and Xi. Now, researchers believe they have identified the missing ingredients.
The two mystery components Jin and Xi were thought to be copper and tin, but a study published in the journal Antiquity suggests they could refer to pre-made alloys used in the production of early Chinese bronzes.
Alloys are made by mixing different metals together. Although they have not determined the exact combination, the researchers are confident that Jin and Xi refer to blends of several metals.
“When you consider the possibility that ancient artisans were using pre-prepared alloys, you get a composition which looks like genuine early Chinese bronzes,” said Pollard.
The discovery was made by looking at Chinese coins from around the time the Kaogong ji was written. The coins seemed to contain two pre-prepared alloys, one copper-tin-lead and one copper-lead, which tipped the researchers off.
“It suddenly struck me that if you reinterpret what Jin and Xi mean, they probably describe pre-prepared alloys,” said Pollard.
The study reveals unexpected complexity in early Chinese metal production. “It implies a whole new stage of metal preparation and supply that we didn’t really know about,” said Pollard.
As well as shedding light on ancient Chinese bronze-making, a better definition of Jin and Xi could help researchers decode Chinese historical texts.
“This research generates an interesting hypothesis about the recipes, introducing the idea of pre-prepared alloys. It potentially gives us an insight into how these people viewed the natural world,” said Pollard.
Prof Lothar von Falkenhausen, from the University of California, Los Angeles, agreed and said: “The idea that Jin and Xi referred to alloys rather than metals seems worth considering as a hypothesis and may be verifiable in further research.”
The Kaogong ji may have served to control bronze production in early China. “The existence of this text suggests there was some imperial control of the production of bronze,” said Pollard. “Bronze was the strategic material in early China, like oil is today. Control over it was key to imperial power.”
“Bronze making was carried out on a massive scale. You need a form of regulation and standardisation to make sure that everybody works closely together,” said Dr Ruiliang Liu from the British Museum.
“The Kaogong ji is a really important document because it describes what people wanted, or what they thought reality should be. Essentially, it is telling us about human behaviour,” said Pollard.
But it may not actually represent the reality of early Chinese bronze production. “It’s a sort of administrative fiction. The sheer scale of what was going on means that we think nobody was truly in control,” said Pollard.
