A Sotheby’s staff member presents a seal from Chinese emperor Qianlong among three Chinese imperial seals during a press preview in Admiralty, Hong Kong on March 1, 2021. The imperial Tanxiangmu "Jingtian Qinmin" seal for the Kangxi Period of China's Qing Dynasty, right, is expected to fetch up to HK$100 million. (CALVIN NG / CHINA DAILY)

The imperial seal of China's Yongle Empress Wen during the Ming Dynasty, left, is expected to fetch up to HK$30 million. It is said to be the only surviving Ming Dynasty imperial seal. (CALVIN NG / CHINA DAILY)

A staff member presents the details of the Qing Dynasty seal from Chinese emperor Qianlong during a press preview in Admiralty, Hong Kong on March 1, 2021. (CALVIN NG / CHINA DAILY)

A staff member presents the details of the Qing Dynasty seal from Chinese emperor Qianlong during a press preview in Admiralty, Hong Kong on March 1, 2021. The seal is expected to fetch up to HK$180 million.  (CALVIN NG / CHINA DAILY)

A staff member presents the details of the Qing Dynasty seal from Chinese emperor Qianlong during a press preview in Admiralty, Hong Kong on March 1, 2021. The preview exhibitions will be held from April 16-22 while the auction is scheduled on April 22, 2021 at Sotheby's Gallery, 5/F One Pacific Place, Admiralty, Hong Kong. (CALVIN NG / CHINA DAILY)