Each unique glaze is not man-made but rather forms its natural and vibrant colors within the kiln. During the firing process in the kiln, factors such as temperature, kiln's environment will form different glaze patterns in each and every Jian Zhan, making them unique to one another. They are not patterns or designs manually applied to the ware but are the results of changes in the glaze itself during the firing process. Within the same kiln during the same firing, a homogeneous glaze will be fired to a myriad of different colours.
The glaze patterns of Jianzhan are currently roughly categorized into six types:
- Black Glaze (乌金)
- Hare Fur (兔毫)
- Partridge-Feather (鹧鸪斑）
- Oil-Drop (油滴)
- Flambe Glaze (耀变)
- Gray Back (灰被)
- Modern Glazes (现代釉)
Traditional Song Dynasty Glazes
In Song Dynasty, only 3 forms of glazes are being recognized. They are Black Glaze, Hare-Fur and Partridge Feather. For those who are antique replica enthusiast. Below are pictorial examples for Song-type glazes:
Black Glaze (乌金)
Black Glaze, also known as Indigo Black, has a smooth surface without any patterns and is a classic glaze colour of Jian kilns.
The glaze color is achieved using iron oxide and manganese oxide as coloring agents. Some glazes appear jet black like lacquer, while others have a hint of bluish black. The finest specimens exhibit a thick and lustrous glaze surface, and in some black-glazed bowls, one can even observe subtle patterns created by the flow of the glaze layers.
Hare Fur (兔毫)
Hare's fur is the most common product of Jian kilns, so much so that people often use "hare's fur bowl" as a synonym for Jianzhan. Hare's fur refers to fine and dense thread-like patterns that precipitate from the black base glaze, resembling the fur on a hare's body.
The shapes of hare's fur patterns vary in length and thickness, with colors including golden hare's fur, silver hare's fur, yellow hare's fur, blue hare's fur, and various other colour furs.
Partridge-Feather (鹧鸪斑）
In the early years of the Northern Song Dynasty, a high ranking court official Tao Gu (陶谷) recorded "In Fujian, tea bowls are made with patterns resembling partridge spots, and they are cherished by tea connoisseurs." From this, the preciousness of partridge spot patterns can be inferred. Partridge feather spots resemble the feathers of a type of partridge bird found only in Fujian province. As far as is currently known, the finest partridge spot bowls are found in Japan, and it is rare to find intact partridge spot bowls domestically in China.
The size of the spots in partridge spots varies, generally taking on a circular or elliptical shape and appearing in colors such as silver, silver-gray and yellow. They may be distributed densely or loosely, resembling oil drops floating on the water, which is why they are aptly referred to as "oil drops" in Japan.
Japanese Tenmoku Classic Glazes
Due to the influence of Song-Type Jian Ware to Japan, Japanese potters started to reclassify Tenmokus' glazes such as Oil-Drop, Gray Back and Flambe Glaze.
Oil-Drop (油滴)
Instead of describing partridge feather spots in Japan, Japanese potters classify them as oil drops instead. The oil drop bowls from the Jian kilns during the Song Dynasty are considered highly prized due to the difficulty in the firing process. Constrained by factors such as body glaze, reducing atmosphere, kiln temperature, the firing conditions are demanding, resulting in extremely rare surviving intact pieces, and complete specimens are also very scarce.
Four years ago, a Song Dynasty oil drop bowl was auctioned at Christie's in New York for about 12 million USD, displaying a well-defined and clear oil drop pattern, finely trimmed shallow ring foot, and an elegant shape despite a slightly asymmetrical distribution. It remains one of the finest surviving oil drop bowls today. In 1935, it was designated as an important cultural property by the Japanese Ministry of Culture. After being released from export restrictions in 2015, it was auctioned in 2016, setting a record for the auction of Jian kiln wares.
Gray Back (灰被)
Ash Glaze (also known as Gray-Back): The glaze is relatively uniform, with a gray-black glaze color. The glaze surface exhibits milky protuberances, and within the overall, gray-toned glaze with a slight hint of black hue.
Gray-Back are known to represent wabi-sabi finishing and is valued in Japan. Wabi-sabi is a Japanese aesthetic and cultural concept that values imperfection, transience, and simplicity.
Flambe Glaze (耀变)
Similar to the term "oil drop," the term "lustrous glaze" also comes from Japan. There are only three Jianzhan with lustrous glaze in the world, all of which are housed in Japan. Among them, the collection at Seikadō is the most famous, often referred to as the "cosmos in a bowl." Additionally, Jianzhan from the collection of Daibutsu Jirō is considered to have a similar lustrous glaze and is called "quasi-lustrous glaze." In 2009, China discovered the "lustrous glaze Tenmoku" for the first time. It was a chance discovery in the process of construction in Hangzhou, represented by fragments unearthed, constituting about one-third of the entire bowl. As of now, no lustrous glaze fragments have been found at the Jian kiln site.
In and on lustrous glaze bowls, irregularly sized circular or nearly circular spots appear on the black glaze surface. The distribution of these spots is not uniform; they may cluster together in groups of several or several dozen. When illuminated by light, dazzling halos of changing colors, such as blue, purple-red, and golden yellow, emerge around the spots. The overall effect is brilliant and radiant, with a shimmering pearl-like luster. This is considered an exquisite masterpiece of Jian kilns. Some researchers believe that lustrous glaze is a special variety within the partridge spot glaze category.
Modern Glazes (现代釉)
With the advancement of science and technology, modern craftsmen are able to create newer and more captivating glazes for the demand of today's Jian Zhan enthusiasts. These are mainly achieved by experimenting with ratios of natural earth materials fired in different atmospheric environment thus creating sometimes unexpected, artistic teacups.
Persimmon Red Glaze (柿红)
Persimmon red, as the name suggests, is the red color reminiscent of ripe persimmons. The glaze surface is not highly glossy, featuring a reddish-brown color with small crystalline points in a deep red hue. This glaze is fired by chance, the original intention is to create hare-fur but due to too high a temperature in the kiln, persimmon red glaze was discovered.
Turtle Shell Glaze (龟背纹)
The name "Turtle Shell Pattern" comes from the crack-like patterns on the surface of the Jian Zhan, resembling the texture found on a tortoise shell. The patterns are coarse, with uneven depths, similar to the patterns on a tortoise's back.
Olive Ash Glaze (橄榄釉)
The glaze surface exhibits a greenish-brown color, is coarse in texture, and has a semi-gloss finish. When observing the cross-section of a droplet of glaze, the interior is a bright black color, with only a thin layer of greenish-brown glaze on the surface.
Ox Blood Red Glaze (牛血红）
The Ox Blood Red Glaze is fired at high temperature displaying a dark or bright red color, reminiscent of oxblood, with blood streaks. It uses rust-colored glazes during firing, and the red colour produced by iron oxide found in it. This firing process requires exquisite craftsmanship and strict operational requirements; hence the oxblood red colour is renowned as a sought after colour in Jian Zhan pottery.
Jade Hue Glaze (玉子)
Jade Hue Glaze resemble a clear green pool in the deep pine forest of the mountains. The glaze exhibits fine crackling patterns distributed throughout the cup. The thicker the glaze at the bottom of the cup, the greener the color.
Wrapped in coarse-textured green imperial jade, this cup combines simplicity with delicacy, ruggedness with refinement.
Blue Kirin (蓝麒麟)
Blue Kirin Glaze is a combination between hare-fur and partridge-feather glazes. This glaze is discovered by chance and does not meet the craftsman's initial intention. Due to the firing process, the glaze underwent a crystallization transformation turning into a deep blue colour with fine cracking lines making the finished product exquisite and special.
Reactive Blue Glaze (回蓝釉)
The reactive blue glaze, as a newly emerged glaze color, possesses a unique and elegantly profound quality. The glaze surface transitions from blue to light with hints of white, resembling the vast sky, the profound sea, and the boundless universe, exhibiting a random and enchanting play of colors. When illuminated by light, it appears as if the cup holds within it the celestial bodies of the sun, moon, and stars.
Pearl Spot (珍珠斑）
The glaze surface of the Pearl Spot Jian Zhan is covered with round and plump white spots, large and bright, resembling pearls in shape, hence the name "Pearl Spot." The white spots resemble "tang yuan" are traditional Chinese glutinous rice dumplings which are consumed during festive seasons symbolizing "reunion with family".
Night of Chrysanthemum (花月夜)
A newly created glaze called "Night of Chrysanthemum" are crystallization on its glaze surface, forming hundreds of blossoming chrysanthemum flowers. Under the microscope, these blooming flowers are truly a breathtaking beauty.