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Photo: Christie´s Images Ltd 2010

The Dr. and Mrs. William L. Corbin collection formed over four decades in the mid 20th century, is a classic example of American taste in Chinese Art. The Corbins carefully amassed an extraordinary group of pottery and porcelain from the Han dynasty (206 BC-AD 220) through the Qing dynasty (1644-1911). Dr. Corbin corresponded with renowned specialists and other like-minded collectors, forming a worldwide fraternity of passionate connoisseurs of Chinese Art. Through the wide range of material offered, with its impeccable and long-standing provenance, collectors will have the opportunity to acquire rare porcelains and works of art from this esteemed collection, thereby passing along the tradition of connoisseurship and scholarship so treasured by Dr. and Mrs. Corbin.

Radiant Colors for the Emperor: Ming Monochromes
In the second year of his reign, 1369, the first emperor of the Ming dynasty, Emperor Hongwu (r. 1368–98), issued an edict which gave imperial monochrome ceramics an important new role. He decreed that thenceforth vessels on the Imperial altars should no longer be made of metal but of porcelain The Imperial altars at which the emperors personally made sacrifices were the Altar of the Sun, which would be served with red porcelain vessels; The Altar of Heaven, which would have blue, the Altar of Earth, which would have yellow glazed vessels, the Altar of the Moon, and a further altar at which offerings using white porcelain vessels were made to the Imperial Ancestors. Red, blue, yellow and white porcelains, like the fine examples in the Corbin Collection, were thus made for use in imperial rituals as well as for other purposes.

The Richest of Reds
Perhaps the most revered monochrome glaze on Ming dynasty porcelains is the rich early 15th century copper red glaze exemplified by this rare Xuande dish.  Firing of this copper red glaze was extremely difficult.  The red glazed porcelains from the Xuande reign are especially favored by connoisseurs because of the perfect combination of rich, deep color and interesting texture of the glaze, and the color red is associated in China with happiness and celebration. The shape of this dish suggests that it could either have been used within the palace or during imperial sacrifices by the emperor.

A rare imperial copper-red-glazed shallow dish, Xuande six-character mark and of the period

Lot 1362. A rare imperial copper-red-glazed shallow dish, Xuande six-character mark in underglaze blue within a double circle and of the period (1426-1435); 2 in. (15.1 cm.) diam. Estimate USD 100,000 - USD 150,000. Price realised USD 362,500. © Christie's Images Ltd 2010

The rounded sides rising from a slightly tapering ring foot to a slightly flared rim, covered inside and out with a bubble-suffused glaze of soft rosy, brick-red tone on the exterior and in the center, shading to a crushed strawberry red below the white rim on the interior, the base covered with a white glaze, box.

Provenance: Bluett, London, 1968.

Note: One of the most widely admired glazes in the history of Chinese porcelain production is the rich copper-red glaze seen on this Xuande dish. Successfully fired copper-red-glazed porcelains from the early 15th century, like the current example, are especially favored by connoisseurs, due to the combination of color and texture of the glaze. Not only is this a particularly beautiful glaze, it is also rare, since successful firing of this copper-red glaze was extremely difficult. This is demonstrated by two dishes excavated from the Xuande strata at the site of the Imperial kiln in 1982. See Xuande Imperial Porcelain excavated at Jingdezhen, Chang Foundation, Taipei, 1998, pp. 93-4 and 265-6, nos. 95-1 and 95-2. On the larger of these excavated dishes the glaze has fired a different color in different parts of the dish, and on the smaller excavated dish the glaze over the whole dish, except for its white base, has an unattractive greyish-tone. The aim would have been to produce dishes with a rich cherry-red glaze, like the current example.

Monochrome copper-red glazes on Jingdezhen porcelain appear to have first appeared in extremely small numbers during the Yuan dynasty, but a clear, brilliant red does not appear to have been achieved. Even in the Hongwu reign (1468-98) of the Ming dynasty, when renewed efforts appear to have been made by the potters to improve copper red, the glazes tended to be semi-opaque and to have a somewhat waxy sheen to their surface. They also failed to reach a good color, and instead varied from an orangey-red to a muddy brownish-pink

In the early 15th century, however, renewed efforts were made at the Imperial kilns to produce a fine copper-red glaze, such as that seen on the current dish. They appear to have made significant changes to the base glaze, which improved the color of the red. There seem to have been three changes made to the base glazes previously used. The potters slightly increased the calcium content, so that the glaze was nearer to the normal lime-alkali glaze used for underglaze blue porcelains. This made the glaze a little more fluid at high temperatures, allowing more bubbles to escape and also allowing more of the batch material in the glaze to dissolve. Both techniques added to clarity of the glaze, although there were still enough bubbles left to create the wonderful curdled texture characteristic of these glazes, which can clearly be seen on the current dish.
The potters also found that if they reduced the amount of copper in the glaze it created a purer red color, since too much copper tends to make the glazes look rather muddy, and they changed from using oxidized copper metal to using oxidized bronze. The tiny traces of tin, lead and antimony present in the oxidized bronze seem to have encouraged the reduction of the copper (Cu+) ions to colloidal copper metal during the cooling process, which helped to enhance the red color. In addition, the Xuande potters at the imperial kilns discovered that the red glazes were most successful when fired to a slightly higher temperature - about 1300o - slightly over the normal 1250-1280. Thus the potters of the early 15th century managed, at last, to produce rich cherry-red glazes, that are often called xianhong or 'fresh red', on porcelains, such as the current example, which remain the most sought-after of all copper-red wares.

It is also noteworthy that following the Hongwu Emperors edict of 1369, requiring that porcelain vessels should be used on the Imperial Altars, red-glazed porcelains came to be used on the Chaoritan, the Altar of the Sun, and hence the glaze on some of these copper-red vessels is called jihong, sacrificial red. Of course, as well as its use in ritual, the color red is associated in China with happiness and celebration.
A small number of Xuande copper-red dishes are preserved in the Chinese palace collections. One such dish in the collection of the Palace Museum, Beijing, which has no reign mark on the base, but retains very feint traces of gilded designs on both exterior and interior is illustrated in The Complete Collection of Treasures of the Palace Museum - 37 - Monochrome Porcelain, Hong Kong, 1999, p. 11, no. 9. Two dishes very similar to the current example were included in an exhibition of Xuande porcelains at the National Palace Museum, Taipei, and are illustrated in Catalogue of the Special Exhibition of Selected Hsüan-te Imperial Porcelains of the Ming Dynasty, Taipei, 1998, pp. 390-1, no. 168 and pp. 394-5, no. 170. (Fig.1). The first of these Taipei dishes bears a six-character underglaze blue Xuande mark on its white-glazed base, while the second bears an incised six-character Xuande mark. Another similar copper-red dish in the collection of the Percival David Foundation bears a six-character underglaze-blue reign mark on its base.

Sapphire Blues
Sapphire blue glazes colored with cobalt became popular in the early Ming dynasty, despite the high cost of the imported cobalt necessary to achieve the finest color.  The most magnificent blue glazes of the Ming dynasty date to the Xuande reign, exemplified by this blue dish.  One of the reasons for the richness of color and texture of Xuande blue glazes is their thickness. Considerably thicker than those of other periods, they give a greater depth and intensity of color.

A very rare imperial blue-glazed anhua-decorated shallow dish, Xuande six-character mark in underglaze blue within a double circle and of the period (1426-1435)

Lot 1361. A very rare imperial blue-glazed anhua-decorated shallow dish. Xuande six-character incised mark within a double circle and of the period (1426-1435); 7 15/16 in. (20.2 cm.) diam. Estimate : $60,000 - $80,000. Price realised USD 254,500© Christie's Images Ltd 2010

With shallow sides rising to a slightly flared rim, finely incised in the center with three wispy clouds, the exterior covered with a deep, rich blue glaze, the interior and convex base glazed white

Exhibited: On loan to the Portland Art Museum, 1 June 2006 - 22 June 2010.

Note: It is generally agreed by connoisseurs that the most magnificent blue glazes of the Ming dynasty were those made in the Xuande reign, and this rare dish from the Corbin Collection, with its beautiful depth of color, demonstrates why this is so. Xuande blue glazes are often considerably thicker than those of other periods, giving them a richness of color and texture. In this reign period fine cobalt blue- glazed porcelain dishes were made either with blue on the exterior and white on the interior, as on the current dish, or with the blue glaze both inside and out.

A dish in the National Palace Museum, Taipei is of the same shape and size as the Corbin dish, and is also blue on the exterior and white inside. It too has an incised Xuande mark (see National Palace Museum, Catalogue of the Special Exhibition of Selected Hsüan-te Imperial Porcelains of the Ming Dynasty, Taipei, 1998, pp. 386-7, no. 166). (Fig.1) On the interior is an impressed design of two dragons. A somewhat smaller Xuande dish in the collection of the Percival David Foundation, London, shares a similar profile to the current dish and that in the National Palace Museum, and has a blue exterior and white interior. The David Foundation piece also has an incised Xuande mark on the base, and incised clouds under the glaze on the interior. Careful examination of the David Foundation dish also reveals, almost invisible anhua slip-painted dragons around the sides (see Illustrated Catalogue of Ming and Qing Monochrome Wares in the Percival David Foundation of Chinese Art, London, rev. ed. 1989, pp. 12-3, no. 511).

The application of fine blue glaze to the exterior of a vessel and white to the interior was not restricted to dishes in the Xuande reign. Excavations carried out in the Xuande strata at the Ming Imperial kilns have revealed a number of other vessel forms that were produced with this arrangement of colors. A stem bowl excavated at Zhushan in 1988 is illustrated in Xuande Imperial Porcelain excavated at Jingdezhen, Chang Foundation, Taipei, 1998, p. 57 and p. 228, no. 52-2, while a straight-rimmed bowl excavated at Zhushan in 1984 is illustrated ibid., pp. 110 and 280, no. 112-2.

The wonderful sapphire blue glazes of the Xuande reign have been given many names in China, including baoshilan, meaning 'sapphire blue', literally 'precious stone blue', jilan and jiqing, both meaning 'blue of the sky after rain', and jilan - using a different ji character, meaning 'sacrificial blue'. The latter name was used because, following the Hongwu Emperor's 1369 edict requiring porcelains to be used on the Imperial altars, certain colors were adopted for certain altars, and blue was used in imperial rituals at the Tiantan (Altar of Heaven).

In order to achieve really beautiful blue glazes the finest cobalt had to be used. Although better preparation methods meant that Chinese cobalt, potangqing, began to be used at the imperial kilns in the Xuande reign, the very expensive cobalt imported from the Middle East was still desired for spectacular blue glazes. The Ming Shi Lu (Veritable Records of the Ming) records an exchange between the Xuande Emperor and his protocol officer in 1431, in regard to a suitable reward for an envoy from Samarkand, who had brought tribute of generous quantities of what appears to be cobalt. The emperor insisted that the envoy be lavishly rewarded (see Urban Council Hong Kong, Imperial Porcelain of the Yongle and Xuande Periods Excavated from the Site of the Ming Imperial Factory at Jingdezhen, Hong Kong, 1989, pp. 73-4).

Time and Place
Junyao vessels with this exquisite glaze were made to contain plants in the imperial palaces and gardens in the late 14th–early 15th century. They were made in various forms and in ten different sizes. The size of each vessel was noted on its base in the form of a number, the current piece likely bearing the numeral one. Such vessels were still treasured items at the court in the 18th century, when they were sometimes further inscribed with the name of the palace in which they were kept, as well as the location within that particular palace.

 

 

 

 

d5348015l

rare 'numbered' junyao hexagonal tripod narcissus bowl.  Yuan-early Ming dynasty, 14th-15th century. Photo: Christie´s Images Ltd 2010

The shallow body raised on three ruyi-head supports and molded with six lobes below the correspondingly lobed and raised outer edge of the everted rim, the interior and rim covered with a pale milky blue glaze thinning to mushroom, and the exterior covered with a brilliant purple glaze with some areas of milky lavender-blue on the underside of the rim and above the base, incised with an effaced numeral yi (one) and covered with a thin olive-brown glaze interrupted by the remains of sixteen spur marks that reveal the grey body; 9½ in. (24.1 cm.) diam., box - Estimate $300,000 - $500,000 

Provenance: A.W. Bahr Collection.
Bluett, London, 1971.

 

Note: The charming six-petalled form of this vessel, which is called kuihua or hollyhock-shaped in Chinese, is complemented by the skillful use of the blue Jun glaze and copper blush. Such stands could either be used on their own as bulb-bowls, or could be used as stands for similarly-shaped and sized plant pots. This is one of an interesting group of numbered Jun wares, which each bears on its base a Chinese numeral ranging from one to ten. Such vessels are made in a limited variety of forms, and the number on the base relates to the size of the vessel. The largest pieces bear the number one, while the smallest bear the number ten. In the case of plant pots and stands of the same design, those bearing the same numeral would go together. Thus the hollyhock-shaped plant pot in the National Palace Museum, which bears the number one on its base, illustrated in A Panorama of Ceramics in the Collection of the National Palace Museum Chün Ware, Taipei, 1999, pp. 76-7, no. 21, would fit with the current stand.

While from the early Qing period scholars dated these numbered Jun wares to the Northern Song period, current scholarship suggests that they were made in the 14th-early 15th century. The only kiln site at which these numbered Jun wares have been found to date is the Juntai kiln in Yuzhou prefecture, Henan province (see Zhao Qingyun et al., "Henan Yuxian Juntai yaozhi de fajue", Wenwu, 1975:6, and Zhang Jinwei et al., Juntai yao faxian yu tansuo, Zhengzhou, 2006), including stands in the same form as the current example (see Sun Xinmin, Henan gudai ciyao, Taipei, 2002, p. 191). These Juntai pieces appear to be of more than one quality, but the current Jun stand is of high quality, comparable to those vessels found in the palace collections, and presumed to have been made for the court.

The current stand was obviously still in use in the palace in the 18th century, and it is then that the two inscriptions were probably incised through the glaze on its base. These would have given the name of the particular palace in which it was kept, written horizontally, and the location within that palace, written vertically. While a later attempt has been made to obliterate these inscriptions, the character gong (palace) can still easily be read, and its style is consistent with inscriptions on vessels still in the palace collections. A comparison of the few remaining parts of the incised characters and their spacing with other extant inscribed Jun wares suggests that the palace name originally inscribed on this stand may have been Zhonghua gong (Palace of Doubled Glory). A begonia-shaped Jun ware stand in the collection of the National Palace Museum, Taipei, which is also numbered one, bears this palace name, written horizontally, and under it, written vertically, the characters Shufang zhai yong (For use in the Study of Fresh Fragrance), as can be seen in A Panorama of Ceramics in the Collection of the National Palace Museum Chün Ware, Taipei, 1999, pp. 124-5, no. 45. It is possible that the current stand also bore this inscription. The Palace of Doubled Glory was situated in the northwest of the Forbidden City, and was part of the private quarters of the imperial family. It was here that the emperor sometimes held tea parties during the Spring Festival, at which guests were required to compose bailing poems. When the Qianlong Emperor ordered an inventory of the paintings and pieces of calligraphy in the imperial palace in 1744, many examples were stored in the Palace of Doubled Glory. The Shufang Zhai (Study of Fresh Fragrance) was in the Palace of Doubled Glory, and was a favourite place of the Qianlong Emperor. The Qianlong Emperor had extensive display shelves for a range of different decorative art objects built along one of the walls of this study, and in this study he often came to share a meal with the Empress Dowager Chongqing. There was even a stage in the courtyard of this study, where operas were performed as part of the festivities at the New Year or on the emperor's birthday. It was also in this study that the Qianlong Emperor used to write the first fu (happiness) character on the first day of the twelfth lunar month. Undoubtedly, the Study of Fresh Fragrance, and the Palace of Doubled Glory, as a whole, would have been elegantly appointed, and the use of the largest of these antique plant holders is quite likely.

Elegant Forms and Refined Colours: Monochrome Ceramics from the Corbin Collection by Rosemary Scott, International Academic Director, Asian Art.

Although when most Westerners think of Chinese ceramics their thoughts turn to blue and white or porcelains decorated in the famille rose or famille verte enamel palettes, traditionally, single-coloured ceramics were amongst the most admired in China itself. It is worth bearing in mind that while extensive decoration can, to some extent, disguise poor potting or inelegant form, monochrome glazes will emphasise every flaw, and need to be applied to beautifully potted vessels. Perhaps it is not surprising, therefore, that the popularity of monochrome ceramics was first established during a period in which the technology and status of ceramics reached an all-time high. It was in the Tang dynasty (AD 618-907) that ceramics were first truly appreciated by Chinese connoisseurs for their own qualities as beautiful objects, and at that time it was not the multi-coloured wares that were the subject of imperial approbation and literary praise, but the monochrome ceramics with plain white glazes or soft, grey-green celadon glazes.

In the Song dynasty (AD 960-1279) the appreciation of monochrome wares grew at courts renowned for their refined sophistication, and among the literati. Both the Northern (AD 960-1127) and the Southern Song (AD 1127-1279) periods saw the development of new kinds of high-fired monochromes which were esteemed by succeeding generations and influenced ceramics produced in later dynasties. Green celadons, white Ding wares, bluish-glazed Jun and Ru wares, Guan and Ge - the crackled celadon-glazed wares of the southern kilns - were to prove the most enduringly appreciated and influential. A fine and direct successor to the Song dynasty Jun wares can be seen in the Yuan or early Ming Jun bulb bowl or plant stand in the Corbin Collection. The charming six-petalled form of this latter piece is complemented by the skilful use of the blue Jun glaze and copper blush. This piece is one of the 'numbered' Jun wares made for the court, bearing the Chinese number one incised into its base before firing. The stand was obviously still in used in the palace in the 18th century, and it is then that inscriptions were probably incised through the glaze on its base giving the name of the particular palace in which it was kept - written horizontally - and the location within that palace - written vertically. While a later attempt has been made to obliterate these inscriptions, the character gong (palace) can still easily be read.

With the beginning of the Ming dynasty and the enthronement of the Emperor Hongwu (AD 1368-98), monochrome ceramics made for the court took on some of the roles previously reserved for bronzes - they were used for state ritual. As early as the second year of his reign in 1369, Emperor Hongwu re-established imperial production at the Jingdezhen kilns in Jiangxi province, and according to the Da Ming Hui Dian (Collected Statutes of the Ming), in the same year he issued an edict decreeing that thenceforth vessels on the imperial altars should no longer be of metal, but of porcelain. While this move was undoubtedly driven by the need to conserve the copper, which would otherwise have been used in the manufacture of bronze vessels, its impact on the porcelains made for and preserved by the Ming and Qing courts was considerable.

The imperial altars at which the emperors personally made sacrifices were the Chaoritan (Altar of the Sun), which would be served with red porcelain vessels - hence the name jihong, or 'sacrificial red' glaze; the Tiantan (Altar of Heaven), which would have blue vessels - hence jilan or 'sacrificial blue' glaze; the Diqitan (Altar of Earth), which would have yellow-glazed vessels; and the Xiyuetan (Altar of the Moon), a further altar at which offerings were made to the imperial Ancestors, which would have had white porcelain vessels. Red, blue, yellow and white porcelains, like the fine examples in the Corbin Collection, were thus made for use in rituals as well as for other purposes.

Perhaps the most revered monochrome glaze on Ming dynasty porcelains is the rich early 15th century copper-red glaze exemplified by the Xuande (1426-35) dish in the Corbin Collection. Not only is this a particularly beautiful glaze, it is also rare, since successful firing of this copper-red glaze was extremely difficult. Copper-red-glazed porcelains from the early 15th century are especially favoured by connoisseurs, due to the combination of colour and texture of the glaze. Porcelains with copper red have traditionally been esteemed for more than simply their rarity and beauty. The colour red is associated in China with happiness and celebration.

Only a very small number of complete vessels or fragments of monochrome copper-red porcelains have survived from the Yuan period, and the glaze did not achieve real brilliance or clarity in that period, even though red, along with blue and white, was one of the important colours in Mongol culture. With the beginning of the Ming dynasty, however, renewed efforts appear to have been made by the potters to improve copper red. In the Hongwu reign (1468-98) copper-red porcelains, despite their new distinguished role, tended to be semi-opaque and to have a somewhat waxy sheen to their surface. They were not the cherry-red of the 15th century pieces, but varied from an orangey-red to a muddy brownish-pink. The base glaze to which the copper was added was somewhere between the glaze used for underglaze blue-decorated porcelains and the glaze used on shufu wares. A quantity of the glaze material remained unmelted in the glaze, and that combined with the dense mass of bubbles in the glaze contributed to its opacity.

However, such was the admiration of the court for copper-red wares that further experimentation was undertaken in the Yongle (1403-24) and Xuande reigns of the early 15th century. The potters of the early 15th century managed, at last, to produce rich cherry-red glazes, that are often called xianhong or 'fresh red', on porcelains which remain the most sought-after of all copper-red wares. There seem to have been three changes made to the base glazes previously used. Firstly, the calcium content was slightly increased. This made the glaze a little more fluid at high temperatures, allowing more bubbles to escape, and also allowing more of the batch material in the glaze to dissolve. Both changes added to clarity of the glaze, although there were still enough bubbles left to create the wonderful 'curdled' texture characteristic of these glazes. Secondly, the potters found that if they reduced the amount of copper in the glaze it created a purer red colour. Thirdly, the potters seem to have changed from using oxidised copper metal to using oxidised bronze. In addition, the Xuande potters at the imperial kilns discovered that the red glazes were most successful when fired to a slightly higher temperature - about 1300.

The importance of white porcelains in the 15th century can be seen from the fact that finds from excavations of the Yongle strata at the Imperial kiln site comprised well over 90 white porcelains. This reign was, of course, also the one in which the famous tianbai or 'sweet white' glaze was established. The tianbai glaze was prized for its soft unctuous feel, reminiscent of jade. Further developments took place in the making of imperial white porcelains in the Chenghua reign (1465-87) achieving, as can be seen from the Corbin white Chenghua bowl, an even greater purity of colour and unctuousness of glaze. The whiteness of the Chenghua porcelain was achieved by very careful preparation of the raw materials resulting in minimal levels of iron oxide and slightly higher levels of aluminium oxide. This very white body material is complemented by a glaze, also containing very little iron oxide, as well as less calcium oxide, resulting in a clearer glaze. Compared to earlier glazes, this glaze has also been described as: '... more softly luminous and more jade-like in appearance'. This jade-like texture is enhanced by the very small, evenly and densely dispersed bubbles in the glaze, which give a softer, smoother appearance when reflecting light.

Sapphire blue glazes coloured with cobalt were applied to porcelains at Jingdezhen in the Yuan dynasty, and became popular in the early Ming dynasty, despite the high cost of the imported cobalt necessary to achieve the finest colour. It is significant that there is a record in the Ming Shi Lu (Veritable Records of the Ming) of a discussion between the Xuande Emperor and his protocol officer in 1431 regarding a suitable reward for an envoy from Samarkand, who had brought tribute of generous quantities of what appears to be cobalt. The emperor insisted that the envoy be lavishly rewarded. The most magnificent blue glazes of the Ming dynasty come from the Xuande reign, as can be seen from the blue dish in the Corbin Collection. One of the reasons for the richness of colour and texture of Xuande blue glazes is their thickness. Xuande blue glazes are considerably thicker than those of other periods, giving a greater depth of colour.

Yellow glazes, including the so-called 'imperial yellow' flourished during the Ming dynasty, and are particularly admired by connoisseurs. The rich imperial yellow first became established on porcelain vessels in the early Ming, but surviving examples are rare, and it is only from the Xuande reign onwards that significant numbers have survived. The beautiful Corbin dish with rich yellow glaze inside and out is a fine example. The colour of this glaze is sometimes called 'chicken fat yellow' in China, and is a low-firing glaze, which, in this case, owes its colour to small amounts of iron oxide. Another Chinese name for this yellow glaze is jiao huang, which can be written using two different Chinese characters for jiao. One means 'elegant', but the other refers to the way in which the yellow was applied to the vessel, as it means 'poured' - suggesting that the yellow was not applied by dipping the porcelain into a vat of glaze slurry, but that it was poured onto the vessel. It seems probable that the pieces classed as 'imperial yellow' were fired at a slightly higher temperature than other, similar, yellow glazes in order to obtain a better colour and clarity. In both the Ming and Qing dynasties this yellow glaze was either applied directly to the pre-fired body or on top of a high-fired glaze. The former method typically gave a warmer colour, while the latter gave a more even, slightly fluid appearance.

Although it is not possible here to provide a full discussion of the varied monochromes in the Corbin Collection, one particularly lovely jar must be mentioned. As previously noted, celadon-green glazes were among the first to be appreciated in the Tang dynasty. These early celadon glazes were applied to stoneware bodies, which were grey in tone, and the overall effect was quite muted. In the early Ming dynasty, however, the potters at the Imperial kilns at Jingdezhen created a highly refined celadon-type glaze, which could be applied to the Jingdezhen white porcelain body. At its best, in the Yongle reign period, this produced the effect seen on the exquisite jar in the Corbin Collection. The glaze colour was achieved by the same basic means as on the early celadon glazes - the reduction firing of very small amounts of iron oxide in the glaze, but with a transparent glaze applied to a pure white body, and the effect was very different. Such pieces are very rare, but two Yongle jars of the same form, with delicate bluish-green glaze similar to the Corbin example are in the palace collections. These are of different sizes. The jar in the Palace Museum, Beijing, measures 14.1 cm. across its base, while the example from the National Palace Museum, Taipei, measures 12.3 cm. Interestingly, these latter jars have three loop handles rising from a quatrefoil base on the shoulder. The Corbin jar would also have had similar handles, but we may assume that at sometime in the jar's history one or more of the handles was broken. However, three flower heads have been carved from the remaining porcelain on the shoulder. It must have required considerable skill on the part of the craftsman who undertook this work, since carving fired porcelain without damaging the surrounding glaze would have been very challenging. It is also a testament to the high regard in which this lovely jar was held by its owner at that time.

1. Da ming hui dian, 'Gongbu' section, in a discussion of qiyong, chapter 201, 2715.
2. The main difference was in the calcium carbonate (CaO) levels.
3. So that the glaze was nearer to the normal lime-alkali glaze used for underglaze blue porcelains.
4. Too much copper tends to make the glazes look rather muddy.
5. The tiny traces of tin, lead and antimony present in the oxidised bronze seem to encourage the reduction of the copper (Cu+) ions to colloidal copper metal during the cooling process, which helped to enhance the red colour.
6. Slightly over the normal 1250-1280
7. The Tsui Museum of Art, A Legacy of Chenghua - Imperial Porcelain of the Chenghua Reign Excavated from Zhushan, Jingdezhen, Hong Kong, 1993, p. 72.
8. Urban Council Hong Kong, Imperial porcelain of the Yongle and Xuande Periods Excavated from the Site of the Ming Imperial Factory at Jingdezhen, Hong Kong, 1989, pp. 73-4.
9. About 3.5
10. Porcelain of the National Palace Museum, Monochrome Ware of the Ming, Book I, Hong Kong, 1968, p. 50, pls. 10, 10a 10b.
11. The Complete Collection of Treasures of the Palace Museum - 37 - Monochrome Porcelain, Hong Kong, 1999, p. 134-5, no. 123.

Christies. Fine Chinese Ceramics and Works of Art.16 - 17 September 2010. New York, Rockefeller Plaza www.christies.com