Kiln Background: The Legend of Cizhou Black Wares
As the largest folk kiln system in ancient northern China, the artistic achievements of the Cizhou kilns extend far beyond their famous black-on-white painted wares. In the production of iron glazes, Cizhou potters reached a level of true mastery. Inheriting and developing the traditions of Tang dynasty black wares, they successfully created a series of precious crystalline glazes during the Song and Jin dynasties by precisely controlling glaze formulas, application techniques, and kiln atmospheres. These included oil-spot, hare's-fur, tortoiseshell, and persimmon glazes, whose artistic achievements rivaled the famed black wares of the Jian kilns in the south, each school possessing its own unique merits.
Form and Function: The Elegance of the Song Tea Ceremony
This bowl and stand set (zhantuo zu) consists of a tea bowl (zhan) and a stand (tuo), which together formed the standard tea equipage on a Song dynasty tea table.
Form: The tea bowl is a classic conical shape with a slightly flared rim; the stand is composed of a raised central gallery to hold the bowl and a wide saucer-like brim with a gently lobed, foliate rim. The stand not only protected the hands from the heat of the bowl but also lent a sense of dignity to the presentation.
Born for Tea: The Song Dynasty was the age of "tea competitions" (dou cha), where the quality of the thick, white froth whisked from powdered tea was prized. Dark-glazed bowls, such as these oil-spot and hare's-fur wares, were considered the best vessels for these competitions because their deep color provided a stunning contrast to the white froth. As the tea was consumed, the magnificent kiln-transmuted patterns at the bottom of the bowl were revealed, offering a moment of aesthetic delight.
The Base and Body: The unglazed foot rings of all four pieces (IMG_6783.jpg, IMG_6787.jpg) reveal the classic buff-colored stoneware body of the Cizhou kilns. The body is hard and has a slightly sandy texture, creating a rustic contrast to the splendid glaze.
Of Stars and Streaks: An Analysis of a Pair of Northern Song Cizhou Ware Oil-Spot and Hare's-Fur Tea Bowl Sets
Oil-Spot and Hare's-Fur Tea Bowl Sets
Era
Northern Song
Kiln
Cizhou kilns
Glaze
Mixed
Oil-Spot glaze
Hare's-Fur glaze
Mixed
SIZE
6.5
x
9.5
x
9.5
CM
This pair of Northern Song Cizhou ware oil-spot and hare's-fur tea bowl and stand sets is a magnificent testament to the glorious peak of black-glazed porcelain in Chinese ceramic history. Not only are they exceptionally rare for having survived as complete sets of bowls and stands (IMG_6782.jpg), but they also showcase two of the most celebrated and technically challenging iron-based crystalline glaze effects: "oil-spot" (youdi) and "hare's-fur" (tuhao). This pair of sets represents both the refined, functional equipage of the Song Dynasty (960-1279 CE) tea culture and a microscopic artistic feast of crystalline beauty, co-authored by the kiln's fire, the element of iron, and the heart of a master potter.
The Art of Kiln Transmutation: Oil-Spot and Hare's-Fur
The most captivating aspect of this pair is that they serve as a "control group," perfectly presenting two related yet distinct iron-crystalline glaze effects.
Oil-Spot Glaze (Youdi): One of the sets is decorated with a dense pattern of distinct, circular spots in silvery-brown or russet tones, resembling droplets of oil floating on water, hence the name (IMG_6786.jpg, IMG_6790.jpg). The spots are scattered across the lustrous black base glaze, shimmering with a metallic light.
Hare's-Fur Glaze (Tuhao): The other set features more elongated, streaky markings. This is particularly evident on the sloped surfaces of the stand (IMG_6784.jpg, IMG_6791.jpg), where the glaze has naturally flowed downwards during firing, drawing the circular spots into fine, parallel lines that resemble the fur of a wild hare.
The Cause: The underlying principle of both oil-spot and hare's-fur is the precipitation and re-oxidation of iron oxides (hematite or magnetite) from a supersaturated glaze during the cooling process. Whether the resulting crystals formed a spot or a streak depended on a host of complex factors, including the viscosity of the glaze, the degree of its flow, the firing temperature, and the cooling speed.
A Microscopic Glimpse: The Blossoming of Iron Crystals
Under high magnification, the dazzling microscopic world of the oil-spot and hare's-fur glazes is fully revealed:
A Forest of Crystals: All of the micro-photographs show that the "oil spots" and "hare's fur" are, in fact, a "forest of crystals" composed of countless tiny, dendritic or feathery structures with a strong metallic luster (IMG_6798.jpg, IMG_6802.jpg, IMG_6806.jpg). These crystals radiate outwards from a central nucleus to form the spots visible to the naked eye.
Color and Luster: Microscopically, the colors of these crystals are incredibly rich, presenting an interwoven palette of silver, gold, red, purple, and blue, all shimmering like a field of stars (IMG_6805.jpg, IMG_6807.jpg, IMG_6815.jpg, IMG_6818.jpg). This is the source of their metallic quality.
The Underlying Matrix: Beneath the crystals, the background black glaze is not a void but is covered in its own fine, web-like network of crazing or micro-crystals (IMG_6800.jpg, IMG_6801.jpg, IMG_6816.jpg). The magnificent "flowers" of the larger crystals have "grown" from this microscopic soil.
Conclusion
This pair of Northern Song Cizhou ware oil-spot and hare's-fur bowl-and-stand sets, with their rare completeness and their perfect presentation of two top-tier black-glaze effects, can be considered a masterpiece from the history of the Cizhou kilns. They are material artifacts of the prosperous Song tea culture and also stand as a monument to the great achievements made by ancient potters in their relentless, scientific exploration of materials. From the beauty of their macroscopic form to the splendor of their microscopic crystals, this pair of sets is an unparalleled exemplar for understanding the art and technology of ancient Chinese black-glazed porcelain.