Which suggests that something akin to the just-in-time production methods used in industry today may have had a trial run more than two millenniums ago.
“Our initial assumption was that all of these items were mass-produced in large production chains, with the various parts produced in specialized units before they were assembled together. That’s how most cars are made — Fordism, or flow-line production,” said University College London archaeologist Marcos Martinon-Torres. He is lead author of the new study, published last month in the Journal of Archaeological Method and Theory. “However, our data strongly suggest that production was arranged in much smaller units, several working in parallel, each of them sufficiently autonomous and versatile to produce finished items,” or what is sometimes called cellular production, lean production or Toyotism.
While archaeologists who have studied the terra cotta army have long thought that a form of mass production must have been in operation, this is the first time that this assumption has been backed up with such precise data.
The scientists came to their conclusion through metallurgical analysis of the weapons and a statistical analysis of where they were found.
First, they studied some of the 37,348 arrowheads found in 680 locations, using a portable X-ray fluorescence spectrometer, a hand-held tool that determines an object’s precise chemical content.
Although the polished arrowheads seem identical to the human eye, X-ray fluorescence revealed that discrete batches of the copper-tin alloys bore unique chemical signatures. Each batch bore its own mix of copper, tin and lead. Different batches were found throughout the site, suggesting that multiple workshops were operating at the same time.
Then the researchers positioned each artifact and warrior on a digital map based on the detailed records created in the 1970s and 1980s by the Chinese archaeologists who first excavated the site.
An illuminating picture emerged. Each quiver seems to have been produced and assembled by a single workshop. The arrowheads were probably made in batches, tied with linen to bamboo shafts, finished with feathers, bundled into 100-arrow quivers of leather and hemp and placed with terra cotta archers armed with crossbows. (The bows’ organic material hasn’t survived the centuries, but 220 bronze crossbow triggers were found.)