[Photo provided to China Daily]

Referring to their rarity, he says: "In historical documents, we found that even though rich people gave tens of thousands of Yue Kiln celadon articles as tributes to royal courts, there were fewer than 200 mise porcelain articles among them."

One of China's top porcelain experts, Geng Baochang, 95, who visited the exhibition, says that the production of mise porcelain was discontinued in the late Northern Song period, and the technique was eventually forgotten.

The last known mise porcelain production was in 1068, according to records of royal tributes.

"Mise porcelain is one of the biggest mysteries in Chinese ceramic history," he says.

"So, it's a major breakthrough to know the whereabouts of the kilns."

Also, compared with other porcelain types, which were exported to Europe, Yue Kiln items are not common.