An imperial portrait depicting Chinese Emperor Qianlong's favorite consort fetched a record $17.6 million on Wednesday at Sotheby's in Hong Kong closing a five-day flurry of sales.

An anonymous bidder prevailed after a 20-minute bidding battle for the painting by Italian court artist Giuseppe Castiglione, the only full-length ceremonial imperial portrait outside the collection of the Beijing Palace Museum, according to Nicholas Chow, Sotheby's deputy chairman, Asia.

"This is a record for Chinese imperial portraiture," he said. The painting, signed by the emporer himself, was estimated to bring $7.7 million.

Sotheby's tally for the series came to HK$2.7 billion ($344 million) for Asian art, watches and jewelry. The total was above the $295 million estimate for the series, but trailed the whopping $540 million sold two years ago. 

A Modern and Contemporary Asian Art Evening sale realized a total HK$596 million (US$76.4 million), and a combined wine sales series brought a total of HK$53,092,225 (US$6,806,695)

Magnificent Jewles and Jadeite brought $HK486,476,250 HKD / $US62,368,750, led by The Jewel of Kashmir, a 27.68-carat Kashmir Sapphire and Diamond Ring which fetched 52,280,000 HKD (6,702,564 USD), reportedly a record price per carat.

The Cowdray Pearls, once owned by an English aristocrat, brought a world record price for a natural gray pearl necklace at HK$41,080,000 (US$5,266,667). In 2012, the same strand of 42 pearls brought $3.35 million at auction.