Visitors look at the ongoing exhibitions that showcase ceramics made in China's porcelain hub, Jingdezhen, for imperial courts during the Ming and Qing dynasties at the Palace Museum in Beijing. The imperial-kiln ceramics represent a zenith in the country's porcelain-making history.

"Chenghua porcelain is an incredible treasure due to its large variety and shapes," says Geng Baochang, 94, one of the country's most renowned porcelain researchers, after visiting the exhibition. "But it was once thought there were not many items surviving from that period.

"So, when the Chenghua works are brought together, it is really a brilliant banquet not only for researchers but also for the public," says Geng.

Meanwhile, another exhibition, Porcelain from the Ming and Qing Dynasty (1644-1911) Imperial Kilns: Archaeological Finds at the Palace Museum and in Jingdezhen, showcases a total of 163 sets from both places, which have been unearthed since 2014, giving visitors a view of how the kilns were managed and how the porcelain was made.

"Some of the finds have filled gaps in academic research," says Lyu. "Many patterns, which are not seen in items which have survived, were found during the excavations."

Examples of how researchers have been helped are the finds relating to the period 1436-64.

The earlier collections did not have any items that could be traced to this period, and this led some to speculate that the kilns had halted operations during that time.