Chinese traditional craftsmanship refers to the collective term for artifacts and corresponding activities created by Chinese people throughout history to meet their material and spiritual needs, using various materials and manual techniques. As an essential component of Chinese art, it embodies the general characteristics of arts and crafts while showcasing the distinct personality of national culture.
Traditional Chinese craftsmanship encompasses techniques such as firing, weaving and embroidery, dyeing, knotting, woodworking, construction, decoration, binding and pasting, cutting and engraving, carving and printing, painting, and molding. It is now commonly categorized into several major fields, including ceramics, metalwork, textile dyeing, lacquerware, furniture, knotting, and sculpture. In this article, the Shanghai Huangpu Traditional Craftsmanship Research Association will provide a detailed introduction to the first category: firing techniques. 1. Firing Technique The initial transformation of clay through firing signifies humanity’s first grasp of fire’s creative potential. From then on, fire became an extension of human creativity. When discussing pottery firing, people often refer to it as the “baptism of fire.” This “baptism of fire” is realized through the effects of temperature and flame on the clay material. “Temperature” refers to the heat level, which is a physical index defining “pottery” and “porcelain” and serves as a technical prerequisite for ceramic art. Generally, the firing temperature for pottery ranges between 700-1000 degrees Celsius, while for porcelain, it exceeds 1100 degrees Celsius. Mature Chinese porcelain is typically fired at around 1300 degrees Celsius. “Flame,” referring to the firing atmosphere, is a chemical factor that determines the color of pottery and porcelain, also acting as a technical foundation for ceramic art. Flames have two properties: oxidation and reduction. The specific nature and variations of the flame directly affect the body texture, glaze color, luster, and surface quality of ceramic products. For example, glaze containing copper will produce a beautiful green or blue color when fired in an oxidizing flame, but will result in a striking red in a reducing flame. For iron-containing glaze, the colors achieved under the two flame types are almost opposite. The traditional white porcelain, described as “white as jade,” is fired using a reducing flame. When discussing pottery firing, “clay” and “fire” are often mentioned together. The body and glaze constitute the fundamental aspects of ceramic “clay.” The body is the structural skeleton of a ceramic object, formed from clay material. Before reaching the sintering point, it is called “green body,” and after sintering, it becomes “fired body.” Throughout this transformation, the “clay material” serves as the basis for unity, not only determining the form of the ceramic but also influencing whether it becomes pottery or porcelain. Generally, clay used for pottery making contains more impurities, while porcelain is primarily made from kaolin-based clay. The former has uneven particles, often includes impurities, and after firing, results in a coarse, porous, opaque, and absorbent body that produces a dull sound when tapped. The latter features fine, uniform particles and pure composition, leading to a dense, translucent, and non-absorbent body that emits a clear, resonant sound when struck.After firing, the ceramic body becomes hard, dense, and semi-transparent with minimal water absorption, producing a clear, resonant sound when tapped.
Glaze, also known as glaze coating, is a transparent or semi-transparent, colorless or colored glass-like layer applied over the ceramic body. The primary component of glaze is glaze stone, which is crushed, refined, and mixed into a slurry before being applied to the shaped body. Glaze has a lower melting point than the body, exhibiting strong tension and fluidity, resulting in a smooth, even surface after firing. In addition to physical and chemical properties such as wear resistance, corrosion resistance, and impermeability, glazing ceramics is akin to adorning them with a radiant, magnificent garment, enhancing their brilliance. Ceramic craftsmanship, as recorded in the ‘Artificers’ Record’ with the term ‘tuán zhí zhī gōng,’ refers to potters. ‘Tuán zhí’ means shaping clay into ceramic bodies by hand. Coiling is one of the most primitive forming techniques, alongside pinching and coil building. The later emergence of mold-making and wheel-throwing techniques revolutionized pottery-making. Wheel-throwing technology initiated China’s millennia-long tradition of potter’s wheel forming, making round vessels the dominant form. Painted pottery unearthed at the Xi’an Banpo prehistoric site exemplifies this tradition. Beyond round vessels, traditional ceramic ware includes ‘zhuó qì’ (non-round vessels). Broadly, zhuó qì refers to vessels not formed on the potter’s wheel into round shapes, such as square, fan-shaped, ribbed, or various irregular forms. Most objects worldwide feature decoration, with traditional Chinese ceramic art particularly showcasing decorative ingenuity. Traditional Chinese ceramic decoration techniques broadly fall into six categories: carving and engraving, appliqué and embossing, mold imprinting, glaze coloring, slip decoration, and painting. Carving and engraving involve incising, dotting, or镂 carving patterns onto the body, sometimes on the glazed surface, as in carved porcelain. Mold imprinting transfers patterns onto the body during forming using molds. Appliqué and embossing use clay to build up relief designs directly on the body or attach pre-made clay pieces. Glaze coloring employs various colored or colorless, transparent or semi-transparent, high or low-temperature, glossy or matte glazes directly for decoration, sometimes painting with colored glazes. Slip decoration uses a slurry of fine clay or porcelain clay applied to the body to mask the surface and reduce absorption of the glaze. Painting under glaze (e.g., underglaze blue, underglaze red, underglaze polychrome) involves applying designs before glazing and firing, while overglaze painting (e.g., famille verte, famille rose, new enamels, cloisonné) involves painting on the fired glaze followed by low-temperature firing. These six decorative methods are often combined in ceramic ornamentation. Regarding the origin of porcelain, academia holds two views: one suggests that the white pottery from the late Neolithic period (e.g., from the Dawenkou culture) represents ‘primitive plain-fired porcelain.’ The Shang Dynasty developed celadon glaze, evolving into ‘primitive celadon porcelain.’An alternative perspective posits that mature, true porcelain emerged during the Eastern Han Dynasty, while earlier glazed vessels are classified as ‘high-fired glazed pottery.’ A significant reason for this divergence in views is the ‘lack of a universally accepted scientific definition of porcelain.’ In reality, all developments follow a progressive course, and in this sense, the two perspectives can be harmonized. Proto white pottery marks the definitive inception of porcelain elements, such as the use of kaolin clay and firing temperatures exceeding 1000°C, whereas celadon from the Eastern Han represents the full realization of these elements.
From the Neolithic Age to the Han Dynasty, the Jiangsu-Zhejiang region remained a primary production area for celadon-glazed ware, or proto-celadon. During the Wei, Jin, and Northern and Southern Dynasties, China entered the ‘Age of Porcelain,’ with distinct stylistic differences between northern and southern celadon forming two major production systems. In terms of glaze, northern celadon exhibited yellowish tones, while southern celadon displayed a more vibrant bluish-green hue. This period saw four major kiln systems in Jiangsu-Zhejiang: Yue, Ou, Wu, and Deqing Kilns. The Yue Kiln, acclaimed as the ‘foremost among kilns,’ reached the pinnacle of Chinese celadon art during the Tang Dynasty. Poet Lu Guimeng praised it: ‘When the Yue Kiln opens to the autumn wind and dew, it captures the emerald hues of a thousand peaks.’ This ’emerald of a thousand peaks’ poetically depicts the luminous glaze of Yue ware. Its beauty earned imperial favor, leading to official supervision and the designation ‘Mystery Color Porcelain.’ In the Sui Dynasty, Chinese potters achieved white porcelain, a monumental accomplishment that ended celadon’s dominance and established a new ‘southern celadon, northern white’ paradigm. White porcelain demanded advanced techniques to minimize iron content in materials and precisely control firing conditions. The Hebei Xing Kiln rose in the early Tang, renowned for its simple, elegant white porcelain, rivaling the Yue Kiln. White porcelain offered a fresh visual appeal, quickly becoming fashionable and widely used across social strata. Additionally, Tang advancements included decorative methods like colored glazes, underglaze painting, and marbled clay, paving new paths for ceramic ornamentation. Tang Sancai, evolving from Han lead-glazed pottery, vividly reflects the era’s grandeur and brilliance. The Song Dynasty represents the zenith of traditional Chinese ceramic aesthetics, with the Five Great Kilns—Jun, Ru, Guan, Ge, and Ding—achieving unparalleled excellence, elevating China’s porcelain craft to its historical peak. Among these, Ru, Guan, and Ge Kilns continued the celadon tradition as official workshops. Ru ware (from Linru, Henan) often featured undecorated forms, with fine, moist clay bodies and lustrous, thick glazes resembling accumulated fat. Optimal pieces had subtle ‘pinhole’ pores revealing a copper-toned body, with powder blue as the standard color. Guan ware commonly exhibited glazes thicker than the body, clustered tiny bubbles (‘gathered foam and clustered pearls’), and natural crackle patterns (‘crab claw marks’). Edges or ridges showed thin glaze revealing a purplish body tone, while unglazed foot rings appeared iron-red or iron-brown, known as ‘purple mouth and iron foot.’The kiln site of Ge Kiln remains undiscovered to this day. According to legend, during the Southern Song Dynasty, the Zhang brothers were both skilled kiln masters, each operating their own kiln in Longquan, Zhejiang. The ware produced by the elder brother became known as Ge ware. Surviving Ge porcelain typically exhibits a ‘purple mouth and iron foot’ appearance, with a thick, translucent glaze that is smooth and lustrous like butter. The glaze surface often features network crackles, overlapping ice crack patterns, or fine ‘hundred-fold fragment’ cracks, predominantly in reddish-yellow (commonly called ‘gold and iron threads’) or blackish-purple hues.
Although Longquan Kiln (also known as ‘Di Kiln’) is not listed among the Five Great Kilns, it is renowned for pushing the limits of thick glazes, such as in the ‘plum green’ glaze, which captures the beauty of jade-like celadon hues. Jun Kiln (in Yuxian, Henan) also belongs to the celadon family. Its wares uniquely utilize the random variations of copper elements in the raw materials and reducing atmosphere, producing natural, serendipitous beauty in bluish-red tones, reminiscent of ‘sunset purples and emeralds suddenly transforming into mist.’ The standout achievement of Jun Kiln lies in its creation of multi-colored glazes, breaking away from the monochromatic tradition of celadon. Ding Kiln (in Quyang, Hebei) primarily produced white porcelain, known as ‘white Ding,’ alongside colored glazes and white-glazed carved wares. Based on color, there are red Ding, purple Ding, green Ding, and black Ding glazed wares. The most notable achievements of Ding Kiln are its carved, incised, and printed decorations, which transformed the monotony of plain white porcelain. Additionally, the practice of adorning the ‘unglazed mouth’ (a rough rim formed during firing) with copper, gold, or silver combined aesthetics with functionality. The white Ding glaze is milky white, imparting a more jade-like quality compared to Xing white porcelain. With the Mongol Yuan rulers favoring white porcelain, celadon gradually declined. The rapid advancement of white porcelain paved the way for the rising dominance of painted ceramics during the Yuan, Ming, and Qing dynasties. This era began with the sudden rise of underglaze blue-and-white porcelain, followed by the celebrated techniques of blue-and-white doucai and filled colors, Kangxi’s gucai, Yongzheng’s famille rose, and Qianlong’s enamel colors. In the realm of monochrome glazes, the Yuan Dynasty’s underglaze red initiated a series of developments, succeeded by a succession of glazes such as sacrificial red, Lang red, rouge water, jade green, and countless color glazes from the Qianlong period, appearing like a brilliant rainbow across the sky, creating a spectacular and colorful panorama.