CERAMICS
Description
Ceramics (yakimono) can be divided into two main types by material: earthenware/stoneware (tōki), which is predominantly made from soil-based clay, and porcelain (jiki), which is made from mineral-based clay. The materials are mixed with water to produce clay. The resulting clay is formed into dishes, pots, vases, or other items that are then fired at high temperatures in a kiln. Japan’s ceramic traditions developed in accordance with the clay of each region, and as a result, many of the crafts bear the name of the region where they were made.
Process
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1 Clay preparation
Quality soil or stone is gathered and made into clay.
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2 Shaping
A potter’s wheel is used to shape round dishes, pots, and vases. Other common methods include hand-layering coils of clay to create forms or hand-building three-dimensional objects from thin slabs of clay.
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3 Bisque firing
Unglazed pieces of pottery are fired at temperatures between 600℃ and 950℃ , which hardens them and makes them easier to glaze.
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4 Glazing
The surface of the pottery is coated with a glaze that vitrifies when fired, producing a layer of glass over the piece.
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5 Kiln firing
The length of time and temperature of firing varies depending on the type of clay and the glaze applied. After the piece has been fired and hardened, it is complete.
Artistic Techniques
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Iron underglaze
Iron underglaze decorations (tetsu-e) are achieved by painting designs in a pigment containing iron oxide. The piece is then coated with a transparent glaze and fired at a high temperature. This basic method of ceramic underglaze decoration relies on the color changes displayed by iron oxide when it is exposed to heat.
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Blue underglaze
Blue and white porcelain (sometsuke) is made by painting blue underglaze decorations on white bisque-fired pottery using a cobalt-rich pigment known as zaffer (gosu). The piece is then coated with a transparent glaze and fired. This technique for making blue and white porcelain has been used in China since around the twelfth century during the Yuan Dynasty.
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Overglaze enamel
Overglaze enamel decorations (iro-e, literally “colored pictures”) are achieved by applying designs to the surface of already glazed and fired porcelain. The decorations are painted over the glaze, and the piece is fired again at a low temperature of approximately 800℃. The pigments used in traditional overglaze decorations are known as wa enogu (“Japanese paints”) and offer a palette of colors such as red, blue, yellow, green, and purple. Overglaze enameling may also be done with Western pigments (yō enogu).
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Celadon
Pale-blue celadon porcelain (seihakuji, known as qingbai in Chinese) is made from porcelain clay derived from white stone. The porcelain is bisque fired and then covered with a glaze containing minute amounts of iron, which turns a blue tint when fired. Celadon originated in China. White porcelain made with a glaze that turns transparent when fired is called hakuji (“white porcelain”), while pieces made from porcelain clay containing iron and coated in a glaze that turns a bluish-green when fired is called seiji (“celadon” or “green ware”).
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Inlay ceramics
Inlay (zōgan) ceramics are created by making incisions on the surface of a piece which are then filled with a differently colored clay to create a design. After the clay is inlaid, a glaze is applied and the piece is completed upon firing.
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Marbleized clay
Marbleized clay (neriage) ceramics are made by layering or combining different colors of clay. A wide variety of patterns can be produced depending on how the clays are combined, with the cross-sections of the finished pattern appearing on the surface of the piece.
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Reference: Nihon Kōgeikai Higashi Nihon Shibu (Japan Kōgei Association Eastern Branch), ed., Dentō kōgei-tte nani? – miru, shiru, tanoshimu gaido bukku (What Are Traditional Crafts? –A Guidebook to Seeing, Learning, and Enjoying). Unsodo, 2013.
Well-known crafts
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Hasami wareOpen in new window
The most notable aspect of Hasami ware is the beauty of its white porcelain and quasi-transparent indigo blue gosu porcelain. Also this craft has kurawanka bowls, sake export bottles and break resistant tableware.
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Mashiko wareOpen in new window
The clay used in Mashiko ware is rich in silicic acid and iron with a high plasticity, making it easy to shape and highly fire-resistant. Unlike other potteries, no extra ingredients are added to the clay which is the secret behind the thick texture.
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Kutani wareOpen in new window
The distinct features of Kutani ware are vivid colors, bold and elegant designs, and a particular technique of overglaze enamel painting. This technique consists of using pigments to paint a pattern incorporating flowers, birds, or natural scenery over a glaze and then firing the piece again.
photo: Ishikawa Prefecture
Tourism League
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Shigaraki wareOpen in new window
Shigaraki ware uses coarse soil, is highly fire-resistant and acquires pink or other shades of red during the firing process, becoming red with scarlet or brown overtones. Due to ashes from the kiln sticking to the surface, the clay takes on a scarlet glow and warm coloring, a characteristic unique to this craft.
