"The shapes, patterns and production skills all went in a new direction, and local bronzeware in China saw a boom in production," he explains. "It contributed to the spread of bronzeware in East Asia, which was like a wave."

The researcher has also cooperated with Tang Chung, a professor at the Chinese University of Hong Kong, to understand the global significance of Erlitou turquoise through comparative studies.

"China was one of the earliest regions in the world to use turquoise," Tang says. "It appeared about 8,000 years ago in Jiahu (an archaeological site in Luohe, Henan), and China's technology for processing it probably led the world for a long time.

"However, importance of Chinese turquoise was barely noticed, because the tradition faded away after it reached its peak during the Bronze Age," he notes.

"More studies on the production system of our turquoise in Erlitou can also better reveal the social structures of the era."

As for the solution to the Xia puzzle, new clues continue to be found that cast new light on the conundrum.

Li Weiming, a researcher at the National Museum of China, while studying an ox bone that was unearthed in 1991 in Mixian county, Henan, stumbled across two carved symbols that looked like Chinese characters. After further examination of the bone-which dates back to the Erlitou Culture period-and analyzing the evolution of various characters, he identified one of them as xia.

"A single example may hardly count," Xu Hong says. "But if, in the future, similar characters are found at the Erlitou site that potentially change history, I will not be surprised."