Juntai ware

Author: Zhao Qingyun / Country: Mainland China
Publisher:
Publishing Date: 2001-01-01
Features: The Jun porcelain kiln was developed based on folk kilns. Jun porcelain originated in the Tang Dynasty and gradually matured by the early Northern Song Dynasty, with the Shenniu Liuzhuang kiln in Shenniu as its representative. The successful firing of copper-red glaze in Jun porcelain, with its colorful and beautiful effects, was favored by the Northern Song court and also popular among the people, leading to the widespread production of Jun porcelain by various kilns. In the late Northern Song Dynasty, during the reign of Emperor Huizong, the folk kilns near the ancient Jun Platform in Shenniu City were monopolized by the imperial kiln, which then specialized in producing Jun porcelain exclusively for the court. The types of wares were changed from the original daily household items such as bowls, plates, lamps, basins, bottles, pots, jars, and vases to decorative porcelain and art objects favored by the court, with more ancient and dignified designs.
The main characteristics of Jun porcelain glaze in the Northern Song Dynasty are low alumina content and high silica content, along with 0.5–0.95% phosphorus pentoxide. In the early Northern Song Jun porcelain, the ratio of silica to alumina ranged between 11–11.4, with 0.8% phosphorus pentoxide. In contrast, the ratio of silica to alumina in official Jun glaze was 12.5, and phosphorus pentoxide ranged between 0.5–0.6%. The red color of Jun glaze is due to the coloration effect of reduced copper, and the amount of copper directly affects the appearance of the glaze. Additionally, variations in the reducing atmosphere and kiln temperature contribute to the poetic colors such as "one color when entering the kiln, a thousand colors when exiting," "no two Jun porcelains are alike, no two kiln changes are the same," and "a thousand Jun transformations, infinite artistic conception."
The prosperity of the Northern Song official Jun kiln coincided with the decline of folk Jun kilns. The Northern Song court, leveraging its power, monopolized the most skilled Yuzhou Jun Platform kiln, turning it into an official kiln and selecting skilled artisans from the folk kilns to work there. They also monopolized high-quality raw materials, produced Jun porcelain with meticulous craftsmanship without cost, and prohibited the continuation of Jun porcelain production in the folk kilns. Official Jun porcelain products were also forbidden from entering the market, all of which suppressed the spread and popularization of Jun porcelain technology.
Analysis of porcelain shard specimens from the late Northern Song Dynasty shows that the technology of the Jun Platform kiln had reached perfection. Except for a small number of daily household items such as bowls and plates, most of the products were various flower pots and accompanying porcelain basins (known as "pot trays"), as well as decorative porcelain like the "" (chzūn) and "" (fèng huá zūn). The designs of these objects were tailored to the court's needs, with flower pots available in various shapes such as (kèihuā shì - peony-shaped), (liánhuā shì - lotus-shaped), (hǎitáng shì - crabapple-shaped), (yǎng zhōng shì - inverted bell-shaped), (zhādǒu shì - zhadou-shaped), (chángfāngxíng - rectangular), (liùjiǎoxíng - hexagonal), and (fāngxíng - square). The bases of most flower pots had five small circular holes, except for hexagonal flower pots, which had seven small circular holes. There were ten different sizes of flower pots, ranging from large to small. Each flower pot was marked with a Chinese number from one to ten (1 being the largest and 10 being the smallest) carved on the base. Each type of flower pot was paired with a matching "pot tray" ( - pén liánr), which had a shallower body, a flat bottom without circular holes, and was designed to hold excess water. The bases of the pot trays were also marked with Chinese numbers from one to ten, matching the flower pots in size and shape.
The "" (chū jǐ zūn) and "" (fèng huá zūn) were modeled after bronze vessels. The Beijing Palace Museum, the Taipei Palace Museum, and the Shanghai Museum all hold Jun porcelain "." These vessels feature a flared rim, a constricted neck, a bulging shoulder, and a trumpet-shaped high foot. Four projections () extend from the neck, belly, and foot, giving them a solemn and elegant appearance. The body is coated in moon-white or lilac glaze, with the edges of the glaze appearing pale yellow where thin. The inner base is coated in sesame-brown glaze and marked with Chinese numbers. The largest surviving example is in the Beijing Palace Museum, marked with the number "" (3), measuring 32.6 cm in height, 26 cm in ( -kǒu jìng - mouth diameter), and 21 cm in ( -zú jìng - foot diameter). The smallest example is marked with the number "" (8), measuring 22 cm in height, 16.6 cm in, and 12.5 cm in .
Among the various Jun porcelain fragments unearthed from the Jun Platform kiln, flower pots and pot trays account for the majority. The glaze colors include uniform sky-blue, sky-green, and monochrome glazes, as well as pots with sky-blue interiors and unpredictable rose-purple glazes on the exterior, and pots with lifelike "" (qiūyǐn zǒu ní wén - worm-trailing-in-mud pattern) on the surface. There are also sky-blue and sky-green glazes, as well as the typical "" (nèi qīng cān zǐ - inner green, outer purple) glaze, with the interior in sky blue (or sky green) and the exterior in magical and beautiful rose-purple, grape-purple, and lilac glazes. These are exquisite works, considered among the finest in Jun porcelain.
In addition to Chinese characters carved on the base, the bottoms of the surviving pot trays from the Qing Dynasty era are marked with regular script such as "" (zhòng huá gōng - Chonghua Palace), "" (jīn zhāo yù cuì yòng - Jinzhao Yucui for Use), and "" (yíngtái - Ying Tai), "" (xū zhōu yòng - Xuzhou for Use), "" (yǎngxīn diàn - Yangxin Hall), "" (míng chuāng yòng - Mingchuang for Use), and "" (shù fāng zhāi yòng - Shufangzhai for Use).
Early Chinese porcelain production primarily used iron as a coloring agent, fired in a reducing atmosphere, resulting in mostly greenish-blue glazes. Through long-term experimentation, (gǔrén - ancient people) realized that controlling and removing iron from the porcelain body and glaze could produce white porcelain. Conversely, increasing the iron content could produce black porcelain. By around 757 AD during the Northern Qi Dynasty, kiln workers had mastered controlling the iron content in porcelain body and glaze, successfully firing white porcelain and breaking the monopoly of early Chinese porcelain with celadon. Afterward, the Chinese porcelain industry maintained a monotonous pattern of coexisting celadon and white monochrome glazes for a long time.
During the Western Jin Dynasty, ceramic production began to master two-color glaze techniques, leading to the emergence of point-painted products. Through evolution and development, Tang Dynasty porcelain produced flower-glazed ware, particularly the brilliant Tang Sancai (Three-Color Glaze) of the mid-Tang Dynasty, marking the ultimate breakthrough from the traditional monochrome glaze framework and opening the curtain for the colorful development of ceramic decoration. The (yáo biàn bān cǎi - kiln-changing patterns) of Tang Dynasty flower-glazed ware laid the foundation for the complex techniques of Song Dynasty Jun porcelain.
Influenced by Tang Dynasty flower-glaze technology, Song Dynasty Jun porcelain, through continuous practice and innovation, added copper oxide to the glaze and successfully fired brilliant porcelain using reducing atmosphere techniques. Song Dynasty Jun glaze is characterized by thick, lustrous, and uniform layers, with a lively, flowing appearance. The glaze is primarily based on red and blue, melting together like flowing clouds and dazzling like evening clouds, with unpredictable variations. Ancient people referred to this as "" (yáo biàn - kiln change). The process of Song Dynasty Jun porcelain is a complex one. Initially, the glaze was sky-blue or "heavy and blue" sky-green, but the addition of copper oxide, through oxidation and reduction, produced red, which blended with the blue to create a beautiful scene of blue with red, red with purple, purple with blue, or alternating red, blue, and purple, resembling roses, peonies, or evening clouds. This basic color scheme, primarily represented by the official Jun Platform kiln, involved applying sky-blue glaze to the interior and red-purple glaze to the exterior, though some applied sky-blue glaze on both sides. Moreover, the sky-blue glaze of official Jun porcelain differed from the pure and uniform folk kiln sky-blue glaze of the early Northern Song period, often featuring a deep blue background with near-moon-white, bead-like flow patterns. The best-fired examples displayed red-purple (yū huái qū zhé - winding and meandering) "" or blue-white flow patterns on a red-purple background. These features align perfectly with the descriptions in 《》 (Táoyǎ - "Pottery and Porcelain Art") such as "the purple of Song Jun permeates the entire body, creating a gradient" and "inner blue, outer purple."
The red in Song Dynasty Jun glaze is due to the coloration effect of reduced copper, while the blue and green glazes contain lower amounts of copper oxide. The purple glaze spots in Song Dynasty Jun porcelain are created by applying a glaze containing copper oxide to the sky-blue or sky-green glaze and firing it in a reducing atmosphere. Variations in kiln temperature and reducing atmosphere intensity cause the copper and iron elements in the glaze to display different colors. The range of variations is so vast that ancient people used phrases like "one color when entering the kiln, a thousand colors when exiting," "no two Jun porcelains are alike, no two kiln changes are the same," and "a thousand Jun transformations, infinite artistic conception" to describe the richness, flexibility, and magical subtlety of Jun porcelain colors.