A rare Chinese porcelain bowl made almost 1,000 years ago is expected to fetch more than $10 million when it goes under the hammer in Hong Kong next month, Sotheby's auction house said Monday. The flower-shaped Ru dish from the Northern Song Dynasty (1086-1125) features six sharp notches on the edge and a subtly translucent matte glaze, and is believed to be the only one of its type in the world, Sotheby's said. "The star of the season is the superb Northern Song lobed washer from the fabled Ru kilns," Sotheby's Asia Deputy Chairman Nicolas Chow said. "It is the first time in 30 years Sotheby's has auctioned off a piece of ceramic this rare. I would say this is about the highest degree of rarity you can find." Of the 79 surviving Ru ware dishes, the "Ruyao Washer" is the only one that features an organic floral shape and an opaque glaze, he said. It was expected to sell for up HK$80 million ($10.3 million) at Sotheby's spring auction in the southern Chinese city on April 4. Other pieces to go under the hammer include a large, early 15th-century blue and white dish from the Ming Dynasty (1368-1644), and an Anhua stembowl from the Xuande reign (1426-35) featuring dancing dragon motifs. More than 380 lots with an estimated worth of more than HK$650 million will be sold at the auction, Sotheby's said. Hong Kong has emerged as one of the biggest auction centres after New York and London. Chinese art prices have rocketed in recent years, fuelled by China's economic boom and a steady demand from rich Asian collectors, especially mainland Chinese buyers. But a Sotheby's auction of imperial Chinese porcelain this time last year sold for less than pre-sale estimates.