The show features more than 130 objects, including the Ming Dynasty ingot in 50 tael, excavated from Sichuan's Jiangkou site, another Ming era ingot and a Qing Dynasty ingot. [Photo provided to China Daily]

He calls it "the most important and largest silver discovery from the Ming period".

Ten of the ingots are being shown at the Shanghai exhibition.

"We picked the most representative pieces with inscriptions that show when and where they were molded, and how much each weighs."

This information made it easy to track down any foul play or mistakes during the production and transportation process, Liu adds.

In ancient China, the tael was the basic unit by which silver and gold were measured.