Theory of Art Creation 10 "What is Celadon?"

Celadon is a type of ceramic ware that is fired with a celadon glaze that changes color from blue to green. Alternatively, it is pottery that turns blue when fired with a reducing flame due to the iron contained in the glaze . This is often said, but what is especially sought after for celadon is high dignity . This is because celadon originally originated as special vessels made for and beloved by Chinese emperors. Its shape is also modeled after bronze vessels that were originally used in religious ceremonies. And the color must be "jade." In other words, the ideal was to imitate jade. By adding the color of jade to the shape of bronze vessels, celadon could become the most noble vessel.

Celadon wheel flower bowl, Southern Song official kiln, China, Southern Song period, 12th to 13th century

Celadon began as pottery covered in a simple ash glaze made from dissolved plant ashes. When trace amounts of iron were added, it was fired at high temperatures in a kiln using firewood or coal under a reducing flame (a state of incomplete combustion with a lack of oxygen). The primitive ash glaze, which would have turned brown in an oxidizing flame, was transformed into celadon that shines in green or blue. This process was improved upon over 2,000 years ago , and beautiful vessels were created as China's pottery technology evolved.

Celadon Phoenix Ear Vase, Longquan Kiln, Southern Song Dynasty, China, 13th century

The unique beauty of celadon is most clearly expressed in its colors. Its mysterious color, which can be seen as both green and blue, is not the result of simple paint, but is produced by a special principle in which a glaze containing iron turns blue when fired in a reduction flame. Celadon glazes are "bluish" and are by no means a uniformly blue glaze. They are fundamentally different from homogeneous blue glazes colored with pigments such as cobalt, and their colors are complex, sometimes showing different expressions depending on the sunlight and the intensity of the light. When viewed in natural light, they appear clear blue in the daytime under strong sunlight, changing to green in the evening, and their color tone changes from moment to moment throughout the day. This mysterious change is one of the greatest attractions of celadon.

Celadon Jade Pot Spring-Shaped Vase, Longquan Kiln, Yuan Dynasty, China, 14th century

Celadon is widely believed to have originated in the middle of the Later Han Dynasty (25-220 AD) in the area around the middle reaches of the Cao'e River in Zhejiang Province. Going back further, we can reach pottery that appeared in the middle of the Yin Dynasty (1600-1028 BC) that was made by applying an ash glaze to the surface and firing it at high temperatures, but this was semi-porcelain and the glaze was gray-yellow or gray-green, so it is too early to categorically call it "celadon" (it is generally called "primitive celadon"). Celadon, which showed a tentative form in the Later Han Dynasty, continued to be refined in color, shape, and design, and was passed down to the Yue kilns of the Tang Dynasty, the Ru kilns of the Northern Song Dynasty, and the Longquan kilns of the Southern Song Dynasty. Of these, the celadon from the Yue kilns was given the special title of "secret color." A record from the past states that "Yaki-shin from Etsu Province was used as a tribute and was not available to ordinary ministers, so it was called a secret color" (Kousai Manroku), which shows that it was a special item that only aristocrats could use. A poet of the time is said to have lamented the gentle olive color, saying, "It has captured the green color of the thousand peaks."

Hazan Itaya, Celadon lotus flower vase with ears, 1944

Celadon from Ryusen kiln is generally characterized by its beautiful powdery blue color, and in Japan it is called "kinuta celadon." One theory behind the name is that when a crack appeared in a Shachimimi vase handed down by the Date clan of Sendai, Sen no Rikyu named it "kinuta" because of the sound of the crack. And it is the celadon from the Ru kiln that surpasses the Etsu kiln and the Ryusen kiln and is said to be the "highest peak of celadon." Compared to other celadons, the celadon from the Ru kiln is said to be closer to the ideal blue, moving away from olive or green tones. The glaze from the Ru kiln is characterized by the fact that it is applied in a single coat, and even though the glaze layer is thin, the color of the base does not show through. This is because a white compound is formed at the boundary between the glaze and the base. The technology that pursued the best blue was truly the culmination of advanced scientific technology.

Mineo Okabe《Hirozan Furnace《Kiln with different rice color《1971

Furthermore, celadon is sometimes decorated with a design called "crazing." Crazing is a type of crack that occurs due to the difference in the shrinkage rate between the clay and the glaze during firing. Some celadon pieces incorporate this as a decoration and even have the cracks colored by painting them with red ochre or ink. This technique is particularly seen in celadon from the Southern Song period, and it is clear that pieces with and without crazing were already being made at that time. These differences in technique indicate that clay with different shrinkage rates had to be used intentionally, and that the production of celadon required highly advanced techniques. On the other hand, there is "blue-white porcelain," a type of pottery very similar to celadon, but this is actually classified as "white porcelain." Blue-white porcelain is made using the same refined porcelain clay with few impurities as white porcelain, and the transparent glaze applied on top of it contains traces of iron, which gives it a blue tinge during reduction firing. Because the porcelain clay is white, and the glaze is not thick, the overall color is a pale light blue.

Shennong Yan, "Jar with Magnetic Lines" 2012

Contemporary artists often write "Celadon" on their celadon works. This indicates that they are creating works in imitation of the Chinese Song Dynasty official kiln celadon, which was mainly made from clay. Artists who create blue-and-white porcelain also use the character "Celadon," and the difference between the two is also apparent in the names. Even today, many artists continue to search for clay suitable for celadon and apply thick layers of glaze with brushes and ladles, pursuing a unique deep blue color. Despite its long history, celadon is still evolving in the modern era.