Ceramic Web Page Tutorials
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(Chinese Ceramics 4.1)

Classical Imperial China
(1) Ceramics of the Sui-Tang Era
ca 600 - 900AD

The Growth of Buddhism
The population of North China was now a wide mix of non-chinese peoples and Han chinese peasantry - with Mongol rulers. Many of the chinese aristocrats and Confucian officials and scholars had fled South as the mongols invaded and Confucianism declined. Buddhism spread from Western Tibet into northern China. Unlike traditional Confucianism Buddhist beliefs included a possible afterlife. This found ready converts in the downtrodden peasantry and it also became popular amongst the mongol population.

Influence of strange and alien imports
Along the western trade (silk) routes to the capital Chang-an came priests, monks and merchants on camels bringing mystical religions and strange exotic people and goods. The style, shapes and patterns of Chinese arts and crafts were greatly influenced by this increasing importation of foreign objects in a variety of alien designs - from woven textiles to silver and wooden articles including many religious objects.

Mongol Rulers adopt Chinese customs
During this time the Mongol rulers progressively adopted traditional Chinese methods of government. Many mongol ruling families intermarried with Han Chinese. The wide differences which had previously developed between North and South China gradually lessened. Northern rulers were increasingly of mixed race families speaking Chinese and adopting chinese cultural manners.

A Sui Reforming Conqueror
The great Tang era is prefaced by the dynamism of a Northern ruler; a conquering General with Tartar and Chinese blood. Yang Chien became the first SUI Dynasty Emperor. He had already carried out many great building projects in northern China, including work on the Great Wall to protect from further invasions. He had constructed a great canal linking the North to the Yangsi river system which dramatically increased the supplies of rice and other goods for the growing population of the north. Trade rapidly increased in both directions. He encouraged the spread of Buddhism and the building of monasteries, but he also persuaded many Confucian scholar-administrators to serve him in the government.

A Reunited China - under the Sui and continued under the Tang
This new SUI Dynasty(580-618) united China. They were led in their campaign to unite China by Yang Chien, who was called Emperor Wen Ti. With increasing prosperity and a new stability spreading from the north it is not too surprising that he easily conquered the South, thus re-uniting the whole of China once again as an Empire under a Sui ruler. Though his reforms and building enterprises were the foundation for the future, the costs in lives and money were high. He was murdered by his son who became Emperor Yang, but he did not last long. The Sui dynasty ended when a Local Governor Li Yuan overthrew him and founded the Tang dynasty to became the Emperor Gaozu from 618-626.

Background History of China There are now an increasing number of excellent Chinese History Internet Sites. The need for my detailed historical background is now diminishing. Check out a brilliant example from Minnesota State University: CLICK: Time lines of Chinese Dynasties.. To Return To My Tutorial Use Internet Explorer Button Screen Top-Left.

A Chinese Golden Age
The population of this new imperial nation was now one of many more creeds and races than the old Han Empire. It became a vibrant, even flamboyant period - as reflected in the colourful Tang earthenware. This dynamism is the product of the mix of changes (economic, social, ethnic and religious) which had gathered pace over the earlier 5th and 6th centuries. All later generations considered the Tang Dynasty to have been a Golden Age.

A Golden Age for Ceramics too
A particularly interesting period for potters. Our ceramic story reflects much of these changes. We find Tang potters in a tremendous surge of creativity; wide ranging technical experiments and aethetic exploration in both high and low temperature ceramics. The three main types are all being produced: earthenware, stoneware and porcelain. We can follow the exploration of bodies and glazes through the Sui and Tang Era. Mixed and overlaid glazes are new and unexpected - particularly the 'suffused' glazes, brush-painted in fluid strokes.

No contemporary ceramic records
Unlike the Middle East and Europe, there is little written in China about pottery technology until very recent times. Although ceramic objects and pottery were admired throughout much of their history, the making and firing techniques of the craft appears to be of scant interest to any Chinese scholar. Obscure hints about pottery making in reports by Chinese civil servants, plus rare examples of drawings on pottery such as the one (Ming Dyn.) illustrated here. This is the nearest we ever get to a picture of the Chinese potter and his craft.
The Emperor's Tax and Tribute Collectors - high ranking aristocratic gentlemen-scholars who wrote such reports would rarely have visited such dirty, dangerous and unpleasant places as pottery kiln villages. Their less cultured minions would go there to collect the taxes and tribute!

Whiter Clays used for both Low and High- fire pottery
Northern wares in Sui and Tang times were made from white and buff-firing secondary kaolins and fire clays at kiln sites located at Tongchuan, Neiqui county in Hebei and Gongxian in Henan. Tang potters used white or buff clays for making both low-fire lead glazed earthenware and high fire ceramics. When fired up to around 1080°C the fired pot pot would still be porous and also reasonably strong. However if fired to temperatures of 1200°C. or above the pot would become nonporous and very strong.

Possible Kiln Forms in Northern China
LEFT 12068 Updraft Kiln RIGHT 12069 Updraft-Downdraft Kiln.
The Sui and Tang kilns in the North were either simple updraft kilns or more complex updraft/downdraft kiln; all fired with coal. These diagrams give some idea of how these kilns probably worked. They are single chamber kilns; quite different from the climbing kilns of the South.

12067 Bun-shaped kiln (man tou yao).
This is part of the painting on a Ming dynasty 14th-16th C. Porcelain vase in the Golestan Palace collection, Iran. This is a cartoon-like image depicting two kilns: Steam bun-shaped kilns (man tou yao). Other descriptive types were: egg-shaped kilns (dan xin yao) and the earliest primitive type, the Yangshao Neolithic kiln (heng xue yao). Some very ruined kiln foundations are the only evidence that remains of such kilns.These images were made much later than the Tang dynasty. They tell us very little. One kiln appear to contain vast numbers of unglazed bowls, the door of the other kiln is bricked up and from the smoke coming from the ring of vents near the top this could indicate a downdraft kiln. In the foreground they appear to be packing dishes into panniers to be carried away on a donkey. There are more questions than answers!

Vast Supplies of Coal in Northern China
By contrast with mountainous central and southern China, wood was not so plentiful on the plains of the north. However there were vast supplies of coal which could be dug out. Earliest supplies would have been open cast coal but later on the coal was deep mined. But the smoke from coal was dirty. This hadn't mattered in earlier ages when coal was used to fuel Shang bronze furnaces and fire mostly unglazed pots, down to the Han dynasty, but now in the Tang age finer glazed pottery needed protecting from this damaging smoke in the coal-fired kilns.

Coal-fird Kilns, "Saggars" but no Kiln Shelves
Coal brought with it firing problems: sulphur fumes and coal ash blowing through the kiln. This smoke and dust could ruin the glazes and shiny surfaces. The potters solution was to put the glazed pots in fireclay containers with lids. These containers could be stacked in a kiln and the glazed pots inside would be protected from the grit and fumes but fired to the same time and and temperature. We use the word 'saggar' for such fireclay containers. They were made in a variety of sizes and shapes from a local coarse sandy fireclay. They could contain one or many pots. Usually they were made to stack in columns, on top of each other in the kiln. The following images show simple bowl saggars.

Views of a small bowl saggar.

12071 A small bowl saggar to protect a glazed bowl during firing.

Each saggar holds one glazed bowl.

12072-3 Small glazed bowls inside saggars

Of course the bowls would only look like this AFTER the firing!

12079 A stack of seven saggars.
These bowl saggars are made to contain one glazed bowl and also stack on top of each other as shown here with seven saggars in the column. The bottom one would be set in the sandy kiln floor and the top one would become just a lid. The height and number of columns in a kiln would just depend on the size of the kiln.

12075 Kiln loaded with columns of bowl saggars
This diagram shows how such saggars can be stacked into tall columns in a kiln. This was a very economical way of firing large numbers of similar glazed pots with little risk of them being spoilt by the dust and smoke caused by coal firing. Notice no shelves are needed. Indeed kiln shelves weren't common until much later.

"A Pre-glaze or Biscuit Firing"
At this point in our story we come to the technique we nowadays term 'biscuit firing'. It appears that Tang potters making lead glazed ware developed a new pattern of firing their pots. It was probably developed to reduce loss (breakage and cracking caused by the fragility of raw pottery and too rapid heating) and probably speed up production. We are now seeing the growth of a mass-production industry. In effect they began to pre-glaze fire their unglazed raw pots to a somewhat higher temperature (c.1100'C) before glazing. This firing made the unglazed pots less fragile for handling and somewhat less porous. After this, the pots would be glaze decorated in a variety of ways. When finished, the pots were fired at the usual lead glaze firing temperature, (probably under 1000°C). This practice was the beginning of 'biscuit' firing - to be widely used much later in mass-produced pottery industries all over the world.

Tang Lead glazed ware

Han Kilns Destroyed
Examples of Han Glazed Earthenware.
Most if not all of the Han earthenware kiln sites were in north China provinces near the capital cities and were probably destroyed during the the disorder and invasions following the Han collapse. Lead glazed Han figurines and pottery seem to disappear by the the early 4th century. Probably there was little or no "Fine Ceramics" industry in Northern China for well over a century.

Revival of Lead Glazed Ware in Northern China
12005 Earthenware Jar with brown lead glaze. H:30cm. Tang Henan.
By the late 5th century economic conditions gradually improved and centres of stability began to grow in Northern China. With prosperity lead glazed earthenware slowly begins to reappear. There were significant differences from Han lead glazed ware. The immitation of bronze forms in earthenware is less evident. Simple thrown forms are now more elegant. The glazing in the earliest examples is simple - brushed or dipped in glazes coloured by iron or copper The vogue for colourful and elaborately patterned ceramic figures and vessels to furnish tombs grew to a peak of production during the first half of the 8th century under powerful Tang rulers. These lead glazed ceramics were mostly burial gift vessels and a variety of funerary objects in a range of brightly coloured styles.

Pale grey or white bodies now common
12007 Two lead glazed pitchers showing whitish slip on pale grey bodies. Tang
There were some important differences between the earlier Han and Tang Lead glazed wares. The clay bodies used in Tang lead glazed ware are almost always pale grey/white compared with red clay used in Han ware. If necessary, a fine white slip was also applied. The range of grey/whitish clays being exploited in the north was now used for both low temperature lead glazed ware and highfire ware.

Three Lead Glaze Colourants
12004 Earthenware Globular vase with iron lead glaze. Tang
The most common colourant was red iron oxide - or a red clay. It produces pale ambers through to rich browns and blacks. This pot is made from a whitish body - and possibly covered with a white slip - this produced a particularly beautiful amber colour with the iron glaze. Holding the foot ring with the fingers, it was dipped upside down just to the foot ring in a lead glaze containing a small amount of iron. Lead glazes are quite fluid and a drip of glaze has managed to flow over the slight ridge of the footring.

12009 Earthenware Parrot-shaped pot with green lead glaze.
Copper oxide in a lead glaze produces a range of vegetable greens through to a cold black.

12003 Earthenware Globular Vase cobalt blue lead glaze. Tang
The third colour was made from cobalt, which produced a rich blue with most types of glaze, but the only source known to the Tang Chinese potter was an import of blue (cobalt) glass via the silk route. It was therefore less common, more expensive and more valued!

Potter's Notes(1) on ...  Firing Lead Glazes A lead glaze needs silica (the glassmaker), lead oxide(the flux) and alumina(the stiffener). White clay contains alumina and silica. So different proportions of lead oxide to white clay in a recipe can produce a white vitreous slip, a white glaze or, with the highest amount of lead oxide and a smaller amount of white slip, a shiny almost colourless lead glaze. A rich shiny clear lead glaze matures between about 800-950°C. In balancing these ingredients in such a simple glaze, the brightest gloss comes at a price. Shiny lead glazes reach their maturing point with a certain amount of heat, but with only a little more heat such glazes very quickly become fluid and run. In a large kiln fired with wood or coal precise firing control is difficult. The heat levels in the kiln chamber will vary. During firing when pots in a particular area (say the middle of the chamber) reach the ideal maturing point for the glaze, glazed pots in some other area may not have reached maturing point. also there may be some corners where the glazed are already overfired! The heating patterns in the kiln chamber have to be checked and understood by the potter. The space can then be managed so that most of the pots come close to reaching the ideal maturing point of the glaze during the firing. It is beyond the scope of this tutorial to go more deeply into glaze chemistry and kiln control but this technical background information should be sufficient to understand the range of technical problems involved and appreciate the remarkable and creative skills of the Tang potters.

Sancai (three colour) or polychrome lead glazed ware

(LEFT) 12024 Lead glazed horse. (RIGHT) 12025 Detail of glazed horse.
This model of a horse, and the close-up detail, show the three colours used in Tang lead glazes.

Mass-production techniques
12032 Figurines of Female Musicians from tomb of a Sui General. Whitish body, Lead Glaze. H:17cm Sui Dyn 595AD
By Sui and Tang times court musicians were always female. These pottery figurines were found in the tomb of General Sheng at Anyang. They were part press-moulded and then details modelled. Dipped, head first, in a lead glaze containing no added colourant, The lower part was not glazed; a common technique because lead glazes often run down and spoil other ware beneath. The pale yellow-brown colour of many such 'clear or colourless' lead glazes comes from the tiny amount of iron present in the clay or the lead mineral used in the glaze.

12002 12040 12037 12031
These four figures: A foreign Merchant(Western Asia) and three mature court ladies of the mid 8th century. are a representative group of the vast number of lead-glazed figures part-modelled, part-moulded and produced during the first half of the eighth century for tomb furnishing.
Face and hair were usually not glazed but painted after firing, with water/gum based pigments; flesh colours for the face and solid black for the hair. This soft matt paint contrasted with the high gloss of the glazed costumes giving these figures a real sense of smooth skin, laquered hair and glistening silk. Some of this can still be seen today though with wear, damp conditions and time much of this colouring has usually disappeared.

12043 Heavenly King moulded and sculpted earthenware with three colour glazes and painted decoration. Tang Shaanxi-Henan H:84cm.
The mass produced figures were made in piece moulds - body, legs, arms, hands, heads etc. A figure was assembled from these pieces and luted together with clay slip. 12044 Detail of 12043 showing unglazed face
More individuality was given to the figurines by extra modelling or carving of small details.Figures were biscuit fired to at least 1100°C and then painted with the coloured glazes. The elaborate headgear was not glazed but probably gilded after firing.

The Challenge: Decorated Silver Ware Repoussé, Chasing and Ring matting 12012 Small Lidded Dish Silver, Tang Dyn. Such silver dishes were the origin of a number decorative styles in Tang ceramics. Examine the two following details of this silver lid. 12013 The fine stamped images and patterns on precious metal objects inspired Tang potters to enrich clay dishes and vessels with ornament. 12014 This image shows a rich background texture of tiny rings on a silver box. This is done using a fine ring hammer. It produces the ring-punched ground seen here - a 'ring dotted' stamped textural background. Tang potters tried to emulate such a rich dotted texture on clay pots and dishes. 12077 & 12078 Lidded Pot, Siver gilt. Tang. H:24cm This magnificent silver-gilt lidded pot demonstrates the competition that ceramics faced. Tang potters now explored a variety of decorating techniques to emulate the new fashionable motifs appearing on silverware. They tried to imitate the exotic silver images of birds and monsters by using fine metal stamps (maybe using disgarded engraving or fine metal fabric printing stamps). Detail of Silver-gilt pot. This detail shows clearly the texture of the ring punched ground around the bold shapes of the bird and leaves on this silver vessel. Ceramic techniques developed by Tang Potters Metal pattern stamping: Example 1 and Background dotted texture: Example 2

Potter's Notes(2) on ...  How Tang potters imitated such background texture on pots A white once-fired pottery dish would be first brushed (or dipped) with a colourless lead glaze. The area marked as the background would then be covered with small spots of a wax resist. A colour glaze would then be brushed over to produce the bright baskground. Glaze is water based, so it avoids the waxy resist - which was covering and protecting spots of the clear glaze underneath. After any other glaze decoration, the dish would be glaze fired. The resist would burn off and the 'spots' of the paler yellowish base lead glaze would then appear as a myriad of pale glittering spots enriching the surrounding background colour and setting off the fine stamped motifs in thr centre. EXAMPLE

LEFT 12015 Well-fired example - Small sancai lead glazed dish.
A good example of the use of fine metal stamps to produce crisp designs and separate the different coloured lead glazes. If these lead glazes run a little, the narrow channels pressed into the clay by the pattern stamps separate two different colours quite crisply.

LEFT 12019 Six lobed sancai tripod dish. Tang Henan D:28cm
Earthenware with three colour lead glazes: green, brown and blue on a straw coloured ground. Impressed patterns made with metal stamps
12020 Detail.
A close-up of the centre of the dish. The grooves cut by the metal stamps into the leatherhard clay can be more easily seen.

LEFT 12017 Sancai glazed dish.
The centre of this dish is decorated using the fine metal stamps mentioned.above. The outer part is covered with the textural dotted pattern made as described using resist. All three coloured glazes were used on this dish. It is an excellent example to show how the fine grooves made by the metal stamps have outlined the various motifs and crisply separated the the differently coloured fluid glazes. The success of the resist spotting technique is also beautifully illustrated in the outer amber glazed background; the white dots we see are really tiny holes where the spots of wax resist once were painted on. In these spots we glimpse the sparkle of the clear lead glaze and the white body beneath.

LEFT 12018 Sancai glazed dish.
A similar lead glazed dish but even more heavily decorated with the dotted pattern echoing the textural patterns made on silver plate but perhaps trying to outshine them with colour.

The Influence of the 'Silk Routes' on Tang Ceramics Silk Routes - a term invented by a German scholar in the 19th Century. Many such trade routes existed before the Romans or the Han Chinese, but the wealth of Rome and the lure of silk - this exotic fabric made by the fabled Chins thousands of miles away - certainly helped this trade to expand - using Roman gold. The land routes to China probably reached their busiest during the Tang Dynasty in the 7th and 8th centuries AD. During that time great caravans, formed of up to 1,000 double-humped Bactrian camels, travelled slowly over vast deserts and some of the most inhospitable territory on earth. Caravans heading towards China carried gold and other precious metals, siverware, jewellery, ivory, precious stones and balls of deep blue cobalt glass(cobalt ores were not found in China until later). In the opposite direction went furs, ceramics, jade, bronze objects, lacquer work and iron, as well as the all-important Chinese export, silk. 12026 A Loaded Bactrian Camel * 12076 Buddhist Silver Ritual Ewer * 12027 Camel with carpet and musicians * A Bactrian(Westrn Asia) Merchant This collection of images illustrates the merchandise and religious artifacts that the foreign merchants, travellers, Buddhists and other missionaries brought to the Tang capital. The forms, designs and patterns of such foreign silverware soon found their way onto Tang ceramics. Carpet designs from the Western Asia and textile patterns from India became exotic and fashionable motifs for Chinese craftsmen to add to their own styles.

Overfiring Sancai Glazes

The problems of over and underfiring have been there from the moment glazes were invented. Every kiln chamber, and especially those which are fired with wood or coal, has 'hot spots' and 'cold spots'. Every experienced potter knows of this problem and finds various ways of coming to terms with it.

Tang potters would have faced the common but vexing task of sorting out a kiln load of glazed pots. They would have done what potters through the ages have done: sort the kiln load into Firsts, Seconds, Thirds and Rubbish (or some similar selective process).

Prices then charged for a pot would have reflected this. As an historian I have no records to support this, but as a potter I can be sure that is what happenned.

12016 &An 12048 Over-fired Lead glazed ware.
This what can happen if lead glazed pots are over-fired. The glazed vertical sides are the first to be affected as the glazes run. If the overfiring is not too great, glazes on flatter parts may be less affected. These two examples were saleable since they were found at burial sites. Such examples show the considerable difficulties in firing perfect coloured lead glazed pots.

12046 A fairly good glaze firing
These two lidded jars are quite similar in shape and glaze decoration. The first jar has been fired sufficiently to melt the glaze completely and produce the full colours. The copper-green lead glaze has not moved but the amber-brown iron glaze has just begun to run down the pot. Look at the centres of the flower resist pattern.
12047 Glazes overfired and running
The next jar has been overfired enough to cause the three coloured glazed patterns to run down and considerably distort the design.

Over-decorated and Over-fired
12050 Over-fired sancai vase.
From a distance this looks as if it is simply a sancai vase covered with a mottled green and brown glaze and dotted with a maze of resist spots (showing the light body underneath) which gives a sparkle to the whole form - that is probably why it was bought for a grave or tomb.
However, closer inspection shows that around the middle of the globular body of the pot are four large pressmoulded motifs sprigged on. They should have been a most prominant feature as bold as the decoration on this Silver Ewer 12076 . However, obscured with dripping mixed colours and a far too prominant network of large white spots, the motifs are hardly visible. For the potter, this would probably be a 'third class' pot. Nevertheless, someone liked it, bought it. It was found at a burial site.

12051 Over-fired sancai vase.
This example shows even greater overfiring: the ornament and background have almost become a marbled form in green and brown due to glaze runs. The glaze runs reached the foot of the pot and probably needed to be chipped away from another piece.

12052 Over-fired sancai ewer.
The models for this ewer was made in the Middle East in beaten metal. To the Tang Chinese such ornament was exotic and fashionable. However, much of the interesting detail is obscured because the coloured lead glazes have melted too much and dripped and mingled into one another.

Background Texture Only

12053 Over-fired green lead glaze on small tripod pot
Essentially this has suffered the same fate as the previous examples: overfiring. But, there is no dominant motif nor orornament here, only the overall texture of a fluid glaze, or glazes mingling together. The whole surface is covered and it does appear attractive - and planned. The glaze filled inscribed lines on the shoulder, the flared top and the stubby little feet and the all-over mottled soft green glaze were sufficient to give this pot a place in the market alongside its costly silver original.

12054 Over-fired blue lead glaze on small lidded tripod pot
This lidded example is similar to the previous footed pot but is squatter form. The cold colour and jagged shapes marking the dabs of resist also mark it as different from the previous green glazed pot. However, the cobalt glass used to make this blue glaze was imported and expensive so would have added to its status and value.
Detail This detail is a closer view of the mottled glaze and shows clearly the ragged edge of the blue glaze around the space once covered by the wax resist. Now we can see the protected clear lead glaze underneath. The thin white line shows the edge of the white slip which covered this buff clay body. This white slip has mostly melted away into the clear lead glaze, but has suvived near the bottom of the pot. See the full image.

12056 Over-fired sancai vase
This example shows the same glaze/resist technique of decorating but using more than one colour, over and around the resist. Though overfired and running, the pattern of mottled glaze seems to t drape the shoulders of this vase like a silk scarf in a quite attractive and informal way. There are no painted motifs but there are four or five rows of large wax resist spots and on top iron and copper glazes in long brush strokes. The final textural pattern of the running and mixing of the glazes seems to have been planned rather than an accident. A new painterly style of decoration with glaze is appearing.

A New Painterly Style?

12058 A sancai liddled ovoidal vase, iron and copper glazes brush decorated.
This is an elegant ovoid form. A talented potter decorator produced a simple but beautiful, fruit-like object by a brushing a range of iron glazes and copper glazes in long thin overlappeding brushstrokes. In the firing these liquid dripping glazes blended into an autumnal range of greens, browns and yellows. This superb result could be no accident; it was carefully planned.

12059 Another ovoidal form with a long flared neck. sancai
On a white body already covered with an unfired clear lead glaze, the decorator brushed dots and short marks with both iron and copper lead glazes. The glaze runs which produced when fired produced this leafy treelike pattern. Again these were planned and designed not accidental splattering planned.

12060 Ewer with high neck (sancai)
This jug for tea drinking appears to be made from a red clay. This is quite unusual in Tang lead glazed ware and suggests a small country pottery making simple domestic pots for the village. In any case, with no supplies of a white body available, it was unlikely that such a potter could make finer ware for wider market.

However, when the pot was leather hard, it was first held upside down, holding the foot, and dipped in a white slip. A white ground would improve the appearance and produce a better decorating surface. When dry leather hard, splashes or patches of green copper glaze were dripped almost to the foot, where we can see the unslipped red body. The pot was then glaze fired.

The quick bold brush strokes, the shape and the red body remind me of peasant pottery from eighteenth and nineteenth century Europe and elsewhere. A useful tea pot decorated with arbitary splashes of dripping vegetable green glaze on a creamy white background does have a simple charm and many similar must have been sold to use at home as well as bought as offerrings to the dead.

12061 small basket with twisted handle (sancai)
This last example appears even more speedily decorated than the previous one. The splashes of iron and copper lead glazes which have blended, almost organically, after firing. This is a tiny object and was small grave gift. However, I would expect that some potters made larger versions, decorated in this same fashion for domestic use.

NOTE: Later in the tutorial when we come to study examples of Tang stoneware and porcelain ceramics, we will see this this glaze painting technique used in a most sophisticated way. The term "suffused glazes" is sometimes used to describle this style.

Tang Mabled Earthenware

12063 Pressmoulded dish Marbled Clay Body Lead glazed Tang Dyn
Using marbled clay was practiced elsewhere but with the Tang it becomes an art and part of the mass production technique of press-moulding forms in clay: lead glazed pottery press-moulded using marbled clay. This ware is made using white and red clay bodies.

12065 Pressmoulded cup (top view) made from marbled clay
These two images are of a pressmoulded cup made from marbled clay. The top image shows the view from above.
12064 Pressmoulded cup (side view)
The side view shows that the cup was made in three parts. First the cup bowl was pressed in a mould. Then, from a simple press mould, a plain red clay footring was luted to the bottom of the cup. Finally a mould pressed marbld ring handle was luted on the side with a little slip.

Potter's Notes(3) on ...  Marbled Clay Bodies Brief description NOTE: Marbled Bodies should not to be confused with the method of marbling a clay surface by slowly mixing two or more coloured slips together in a bucket and then dipping or pouring to cover the clay SURFACEof a dish or pot with a marbed effect. In a piece of Marbled Clay Body the marbled pattern goes right through the thickness of the clay sheet. Making: By slowly folding and twisting together balls of red clay and white clay, a marbling effect can be produced. The mixing is done carefully until the desired density of patterning is reached; checked by taking a slice of clay. Slices of marbled clay about 2mm thick are then carefully cut into pieces and cut, pressed and joined in a mould. Simple marbled forms with single slices of clay or complex patterns made by cutting and joining pieces together in the mould. Example

The Rise and Fall of Sancai

Called sancai, three colour or polychrome lead glaze, this style of colourful earthenware pottery from Northern China became an important element in the growth of the mass-production pottery industry in China from the the late 7th century under the Sui Dynasty.

It reached its full flowering and popularity in the first half of the eighth century under the Tang emperors. However, the tragic events of An Lu-shan's rebellion in 755 and the civil war(755-66), which followed, devastated much of North China.

The kiln sites around the Northern capital cities were destroyed and the Tang lead glazed pottery industry never really recovered. The main ceramic activity moved to the more stable South, where the high fire ceramic industry continued to grow.

For more historic social & political detail, you could start with :
Time lines of Chinese Dynasties.T'ang 618-907 A.D.

The next part of this tutorial page will be ready in Spring 2011.