AN EXTREMELY RARE 'SNOWFLAKE-BLUE' INCENSE BURNER MARK AND PERIOD OF XUANDE |

superbly potted with the rounded sides supported on a short straight foot, gently rising to a slightly waisted neck, the exterior covered with a heavily mottled deep cobalt-blue glaze suffused with minute contrasting azure highlights, the interior and the base left white, the latter inscribed with a six-character reign mark within a double circle in underglaze blue

An English private collection.

There is a long Y-shaped crack that runs from the rim stopping around 4 cm above the foot. The crack has an old rivet repair, that now has been removed and restored. There is also a small star crack on the side, visible on the interior. The foot has an approx. 1 cm chip. The glaze is very well controlled and even throughout.
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

No other snowflake-blue censer of this form appears to be recorded, and the 'snowflake-blue' glaze as well as this shape are also outstandingly rare on their own. This low-fired mottled type of cobalt-blue glaze represents one of the most spectacular and surprising developments of the Ming imperial kilns in the Xuande period, and appears to have been one of the most difficult to fire successfully. Only eight other vessels with this type of glaze appear to have survived intact, seven of them thick-walled bowls of Xuande mark and period and one a bowl of the more common flared shape, without a reign mark. The glaze is known under various terms, such as salan ('speckled blue'), xuehualan ('snowflake blue'), or qingjinlan ('metallic blue'). The cobalt glaze mixture is believed to have been blown onto the already fired porcelain body, and to have been fired on at a lower temperature (around 800°-900° C). In a period which otherwise aimed for smooth uniform monochromes, its intentional mottled effect and varied range of tones, from a light turquoise blue to an intense lapis lazuli colour, are unique. Recent excavations at the Jingdezhen imperial kiln site have shown that in the Xuande period experiments with this glaze were made on many different forms, but more unsuccessfully fired and deliberately broken examples were recovered, suggesting that the variations of the glaze all-too-often proved unacceptable to the kiln supervisors and were therefore rejected (for reconstructed fragmentary vessels from the Ming imperial kiln site, see Jingdezhen chutu Ming Xuande guanyao ciqi/Xuande Imperial Porcelain excavated at Jingdezhen, Chang Foundation, Taipei, 1998, pls 15, 114, and f 33-35). The low success rate probably explains the extremely short production period of this type. The technique was never properly revived after the Xuande reign, and when a blown-on cobalt glaze was recreated in the Kangxi reign of the Qing dynasty, the pigment was covered with a transparent glaze and fired at high temperature.

Extant examples include the snowflake-blue bowls with thick walls in the Capital Museum, Beijing, see Shoudu Bowuguan cang ci xuan [Selection of porcelains from the Capital Museum], Beijing, 1991, pl. 104; in the British Museum, London, from the Sir Percival David collection, illustrated in Regina Krahl and Jessica Harrison-Hall, Chinese Ceramics. Highlights of the Sir Percival David Collection, London, 2009, pl. 34; and in the Meiyintang collection, illustrated in Regina Krahl, Chinese Ceramics from the Meiyintang Collection, vol. 4, London, 2010, no. 1666. No example with this type of glaze appears to be preserved in the Palace Museum, Beijing, and the National Palace Museum, Taiwan, only holds an unmarked example of the more common bowl shape with thin walls and flared rim; see Mingdai Xuande guanyao jinghua tezhan tulu/Catalogue of the Special Exhibition of Selected Hsüan-te Imperial Porcelains of the Ming Dynasty, National Palace Museum, Taipei, 1998, cat. no. 131.

The shape of this piece, described in Chinese with the terms bo or guan, is also extremely rare and no such piece appears to have been offered at auction before. A unique monochrome red version, with a cover, discarded at the imperial kilns, was included in the exhibition Taipei, 1998, op.cit., pl. 28, together with two blue-and-white examples, pls 29-1 and 29-2; two other covered blue-and-white bowls of this shape in Taiwan included in Catalogue of the Special Exhibition of Selected Hsüan-te Imperial Porcelains of the Ming Dynasty, op.cit., cat. nos 1-2. The blue-and-white versions all show a peculiar row of thick blue dots inside the rim.