Taniguchi Clay Manufactory 
The clay manufacturing site that supports Kutani ware

Without clay, kutani ware cannot be made.

When people hear about Kutani ware, they tend to focus on the decoration, such as painting and glazing, but it is the clay that forms the vessel and allows the painting to be applied to it. So, the clay. How on earth is clay made?

 

We went to Taniguchi Clayworks in Komatsu City.
Taniguchi Clay Works is a clay manufacturer that has been in business for three generations.
They have developed various types of clay according to demand, and supply clay not only to local potters and artists, but also to people all over the country.
It has also developed an original brand "HANASAKA" that maximizes the appeal of clay.

Koichi Taniguchi, the third generation owner of Taniguchi Clayworks, first took us to Serabo Kutani, a short walk from Taniguchi Clayworks.
Serabo Kutani is the common name for "Kutani Ceramic Laboratory", a complex facility for Kutani ware. Kutani ware is displayed and sold, and visitors can also try their hand at pottery making, hand-painting, and pottery decoration.

Clay making at Taniguchi Clay Mills can be observed at Cerabo Kutani!

Cerabo Kutani has a clay making factory run by Taniguchi Clay Works. The machines are not on display, but in active operation, and the clay made here is actually in the hands of potters and artists. The fact that the entire factory is on display shows how important clay is to Kutaniyaki.
Moreover, the number of clay makers in Ishikawa Prefecture has been decreasing, and now there are only two left (one of them is Taniguchi). (One of them is Taniguchi Clay Mills.) Clay makers themselves are also rare.

It is operated by
Stamper", who continues the old-fashioned method of clay production.

Taniguchi Clay Works uses two types of manufacturing methods to produce clay. One is the "stamper" method, in which ceramic stone, the raw material for clay, is crushed by a machine and then subjected to a process called "water sieving" to produce clay. According to Mr. Taniguchi, "In the raw material, ceramic stone, there are two components in one lump, one of which becomes clay and one of which does not. By pounding it with a pestle-like machine called a stamper, the attached components are peeled off as they are crushed. Once the clay is broken down to a certain degree, it is moved to a process called hydrolysis. Here we remove most of the components that do not become clay.
Although machines are now used to crush the ceramic bricks, the principle of the production process has not changed. We were shown the process in more detail.

Process of clay production made by stamper x water sieving, which requires a lot of time and effort.

1. crushing the mined ceramic brick
A machine called a crusher is used to break the ceramic stone, which is a block of stone, into smaller pieces.

 

2. drying
Hanasaka pottery stone, the raw material used, is highly absorbent of water. Even in its powdered state, it contains a lot of water, so it is dried. The humidity must be just right so that the stone can be evenly crushed with a pestle.


3. apply a stamper

A pestle-like machine is used to pound the potter's stone to further reduce it to a powder. The soft parts of the potter's clay are further ground into a fine powder, while the hard feldspar and quartzite, which are not clay components, are left in pebble-sized pieces. 

 

4. water sieving
The powdered ceramic stone is immersed in water. Since silica and feldspar have a higher specific gravity than clay, they sink to the bottom and separate into a layer of clay and a layer of silica and feldspar. Remove them by scooping.
↓Feldspar and silica contained in Hanasaka pottery scooped out from the bottom.

Repeat steps 1 to 4 to accumulate muddy clay from which the silica and feldspar have been partially removed.
This is the end of the process at Cerabo Kutani. The following is the factory next to the Taniguchi Clay Works office.

 

5. remove other impurities such as iron
Once a certain amount of muddy clay has accumulated, impurities are removed using a vibrating shaker or electromagnet. If there are iron grains, which are impurities, they will leave burn marks of iron powder when the vessel is fired.

 

6. dewatering
The muddy clay from which the impurities have been removed is placed in a dehydrator mold and squeezed to dehydrate it. The squeezed out water falls down and flows away.

Hanasaka ceramic stone has spongy particles and is highly water absorbent. It takes about 10 hours to dry because it contains a lot of water due to the water-weaving process and other factors.

 

7. clay finishing
Clay is sometimes shipped after dehydration, and sometimes shipped after being kneaded and aired in a clay kneading machine.
↓Clay in the clay kneading machine.

It takes about 7 hours with a stamper, although a machine is used. The watering process also takes time. In addition, the stamping x water-hoe process must be repeated to accumulate the muddy clay. And drying takes about 10 hours. We found that it really takes a long time for the clay to be ready.
In addition, I felt that the clay is not completely mechanized, but carefully made by human hands, for example, the grinding time is determined according to the humidity, and there is manual work in the water-building process.

 

Now let's take a look at another manufacturing method.

High productivity is appealing. It supported the era when things sold well.
How to make clay from TRONMILL

1. Putting materials into the TRONMILL
In a huge machine like a mixer, TRONMILL, materials that will become water and clay are put in to make clay. The ingredients are mixed differently depending on the use of the clay to be made. 

 

2. Grinding materials in the TRONMILL
The TRONMILL contains about the same amount of stones as the material, and as the TRONMILL rotates, the stones rub against each other, thus rubbing and mixing the material.

3. removal of impurities and dewatering
After that, the iron is removed with an electromagnet, and the muddy clay is sieved to remove impurities and dehydrated to complete the process.

 

The Tron Mill is a huge machine, even though it is a device; it can produce 2.5 tons of clay at a time. At a time when things were selling well, the production by stamper was time-consuming and production could not keep up, so for the sake of productivity, Taniguchi's father, the previous president, introduced the TRONMILL. Now, they produce various types of clay to meet their needs by changing the formula of the materials.

Two production methods. What are the characteristics of each?

The clay produced by stamping x water mixing is said to be very good for rocro molding. Stamper clay is especially good for making large vessels with a potter's wheel. Mr. Taniguchi also says that the manufacturing process itself is valuable. Stamper is a primitive process, even though we have introduced machines," he says. In other words, there is an added value in the fact that the clay is made in the traditional way. In this respect, I believe that the attractiveness and value of clay produced by stamper will continue to increase in the future," he says.
On the other hand, TRONMILL is a process for making clay by mixing materials. By changing the ratio of ingredients, it is possible to produce clay suitable for different uses, such as clay suitable for casting with good mold release and clay with low shrinkage suitable for tatara molding.

Hanasaka Pottery Stone, the Raw Material

Behind Serabo Kutani, we found Hanasaka pottery stone, which is the raw material. This Hanasaka pottery stone was discovered in the late Edo period. It was discovered in the late Edo period. It was such a great discovery that it is said that if Hanasaka pottery stone had not been found in the Edo period, Kutani ware might not have continued to the present day. In fact, mining of Hanasaka Pottery Stone continues and still supports Kutaniyaki as a raw material.
When we asked Mr. Taniguchi about the difference between good and bad quality pottery stones brought from the mine, he replied, "The difference is whether the stone is weathered or not. Those that have been weathered are of good quality. They are soft and can be easily broken by hand. On the other hand, those that are not weathered are hard. When I heard the word "weathered," I understood that ceramic stone is a precious product that has been nurtured by nature over an astronomical period of time, and that it is this ceramic stone that supports Kutani ware, which has a history of about 360 years.

Kutani ware is indeed a masterpiece of painting.
However, it would not be possible without the clay and pottery stones that form the basis of Kutani Yaki. The charm of Kutani Yaki becomes even more fascinating when you think about clay and pottery.

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