Seto City in Aichi Prefecture is a pottery production center with a history of over 1,000 years.
The reason for this is that the best clay for pottery, called "Gairome," can be extracted here.
Why is frog eye suitable for pottery?
Its main feature is its plasticity, which allows it to retain its shape like a shape-memory alloy, making it very easy to throw on a potter's wheel. It turns pure white when fired and is highly fire-resistant. If you refine it and mix the clay with feldspar and silica, you can even make clay for porcelain.
It is truly a clay that was born for pottery. Thanks to this clay, pottery has been produced in Seto for over a thousand years. However, frogeye is a natural resource that is dug from the mountains, and as it is dug up, it disappears.
I would like more people to know about this.
We spoke to people involved in the ceramic raw materials industry and potteries who work with clay in Seto.
*If you would like to know more about frog eyes, please click here .
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This time, we will be introducing Shin Kama, a blue and white porcelain kiln founded in 1919. They produce Seto blue and white porcelain, which is designated as a traditional craft. The pure white clay is beautifully painted with a moist blue called "Shin Kama Blue," and the kiln has many fans.
The beauty of the painting and the high level of skill make it easy to focus on the painting, but we also got a glimpse into the artist's commitment to the clay.
What is "Shin Kiln"?
The blue and white porcelain kiln "Shin Kama" is located in Shinano, an area of Seto City that is surrounded by nature. The surrounding area is surrounded by mountains, and you can hear the chirping of birds.
At Shingama, third-generation Kato Shinya and Kato Mihoko, as well as fourth-generation Kato Mayuki, the youngest traditional craftsman of Seto Sometsuke ware, work together with several other artisans to create their products.
Sometsuke is a type of pottery in which a design is applied to the porcelain base using a pigment containing cobalt oxide. At Shingama, the painting is done using brushes of various thicknesses, the most representative of which is a brush with very large bristles called a "dami brush."
The rough position is determined on the paper and a rough sketch is made with a pencil. The brush then absorbs the pigment and applies it like a dropper, and the paint is drawn.
The pigment adheres perfectly to the areas outlined with pencil and is absorbed into the base material. The shade changes depending on the speed of the brush stroke, making it difficult to stop and stare.
Elegant and warm sake cups and vases.
About the clay of "Shin Kiln"
The clay used at Shin Kiln is sourced from Maruishi Ceramic Raw Materials, which also cooperates with the exhibition. It is a blend of frog's eye clay, kaolin (New Zealand, Germany, China), feldspar, and Amakusa pottery stone, and is sourced in round shapes called "cakes."
When using the clay, sodium silicate and water are added and stirred to create a mud called "slip."
The clay is transferred to a tank and poured into a plaster mold. Plaster has the property of absorbing moisture, so the outer layer of the slurry hardens first. Wait for about 30 minutes for it to harden.
Once the required thickness is reached, the mold is turned upside down and the excess slip is poured out. This is why the process is also called "gaba-zukumi."
Once it has hardened, it is carefully removed from the mold and the raw clay is ready. At this stage it looks grey, but once baked it turns a stunning white. This is how a white canvas is created.
Commitment to soil
"We don't make the clay ourselves, so we use a firing method called 'nerashi' to show our commitment to the quality of our work."
Said Shinya.
The origins of Seto Sometsuke ware date back to the early 19th century (Edo period). In the early 17th century , Seto was faced with a pottery production competition with Hizen (Saga and Nagasaki) , where white porcelain (porcelain) was first produced in Japan, and potter Kato Tamikichi went to the area.
Tamikichi returned home with the porcelain manufacturing techniques he had acquired. It is said that the techniques he brought with him led to a dramatic development in porcelain production in Seto. Later, a firing technique unique to Seto was developed called "nerashi."
Kyushu's "Amakusa pottery stone" is an excellent pottery stone that can be used alone to produce pure white porcelain, so much so that it is called "white porcelain," but it could not be mined in Seto. Therefore, Seto pursued development by blending frog's eye, feldspar, silica, and other materials to create this pottery stone. However, the raw materials that could be mined were not enough to produce white porcelain, and the result was closer to a gray color. Under these circumstances, various firing methods were considered to make the color of the blue and white porcelain as beautiful as possible.
"In Arita, adding ash from the Distylium racemosum tree improves the color, so Tamikichi brought some back with him, but it didn't really suit the soil of Seto.
When fired at a high temperature of around 1,300 degrees, the base turns white, but with Seto porcelain clay, the blue and white porcelain tends to bleed. For this reason, the temperature is kept lower than that, and after the kiln temperature reaches its peak, the same temperature is maintained throughout the firing. I'm not sure if it's appropriate to call it maturing, but the color gradually comes out on the surface."
Clay has its own compatibility with pigments. At Shin Kama, we continue to use this technique, observing the compatibility with the clay.
Nowadays, due to the demand for whiter clay and the fact that it is now easier to transport clay, it is now possible to obtain whiter clay in Seto by blending Amakusa pottery stone or kaolin from overseas.
White has always been an object of desire, but without high-quality ingredients, it is difficult for white to remain white.
As the soil decreases
At Shin Kiln, they make nearly 30,000 pieces of pottery every year. As Mayuki works every day, she wonders how many pieces she should make, a question she can't answer.
"It's a job, so of course I have to make a lot and sell a lot, otherwise it won't be viable. Would it be better to make the quantity optimal and raise the price a little more? I don't have a solution to this problem, but I often find myself vaguely thinking about it."
He also says that he thinks about defective products every day.
"When you're making something, defects are inevitable, so I feel bad that we're making so many even though we're running out of raw materials. When you're dealing with individual customers, you tend to be concerned about even the smallest details, so your inspection standards become very strict."
True to their word, the products delivered by Shingama are always perfect. Even the way they are packaged is artistically beautiful. Because pottery is made from natural soil, any iron that is not removed from the soil can come out as iron powder during firing.
But is it really so bad that one piece of iron filings would make it unsellable as a product?
However, if I had to choose which one is better, I would choose the one without iron powder.
Pottery is only possible with clay.
On the streets of Seto, there is a quiet shrine dedicated to the god of fire, where people involved in pottery offer prayers, and once a year, purification rituals are held at the mines.
"When we take soil, it means creating a big hole in the earth. We have repeatedly caused environmental destruction, so we need to do something about that too. We need to be grateful to nature. I think that people who make pottery have a strong sense of gratitude."
"Shinya has been making pottery for about 50 years, so his words carry a lot of weight.
[Listening to the Voice of the Soil: Introduction to the Series]
Part 1: From raw soil to clay. [Listening to the voice of the soil. Column on the Kasen Mine]
Part 2: "I want to leave the soil for future generations" [Listening to the voice of the soil: Column on Seto Hongyo Kiln]
Part 3: Craftsmanship is understanding the materials. [Listening to the voice of the soil. "Sakusuke Kiln" column]
Part 4: What happens when you bake clay? [Listening to the voice of the clay. Column by Miyama Pottery Studio]
Part 5: In search of the beauty of white and blue. [Listening to the voice of the soil: Shin Kiln Column]
Part 6: Don't turn it into industrial waste. Think about recycling soil. [Listen to the voice of the soil. "Soujuen" column]
Part 7: What kind of clay is used in ceramic dolls? [Listening to the voice of the soil. Column compiled by Seto Tougeisha]
Part 8: Are the raw materials for pottery and glass harvested from the same mountain? [Listening to the voice of the soil: A column from "Jinya Marusen Ceramic Raw Materials"]
Part 9: Clay making by a long-established clay company founded about 150 years ago [Listening to the voice of the soil. Column on "Maruishi Ceramic Raw Materials"]
