How to make Gosu | Arita's secret method of making Gosu revealed

In this article, we will explain how gosu is made.
In addition to the general method of making gosu, we will also reveal how to make Arita's secret gosu.

There are roughly three ways to make gosu.

1. Mix the mixture yourself and grind it using a mortar and pestle.

You can purchase and mix the raw materials, such as cobalt oxide and iron, to achieve the color of your choice.
This mixed gosu is placed in a mortar and mixed with water or green tea, gum arabic, etc., and crushed with a pestle.
It takes an incredibly long time to grind it down, but because the gosu particles cannot be crushed completely, they still have a grainy texture.
This method is ideal when you want to test colors.

2. Purchase the item on sale and grind it using a mortar and pestle.

Gosu that is generally sold in stores is made through the following four or five steps.

1. Mixture

The raw materials are mixed with cobalt oxide as the main component.

2. Homogenization

Use a mixer to mix the ingredients thoroughly.

3. Firing

The raw materials are placed in fireproof bricks called boshi and fired.
Some companies do not carry out this step.

4. Crushing

The mixture is placed in a machine called a Tron Mill, where it is crushed with water, stones, and gosu.

5. Drying

The gosu crushed in step 4 is dried.

Products made using the above process are suitable for mass production.
Therefore, if you are using it for hand painting, you will need to grind it in a mortar and pestle as you did in method 1.
However, the particles are still coarse, so the brush stops moving when drawing.

In addition to 3.2, grind the rice using a stone mill.

3 is how we make gosu at Shinkai Shoten.

1. Mixture

The raw materials are mixed with cobalt oxide as the main component.

2. Homogenization

Use a mixer to mix the ingredients thoroughly.

3. Firing

The raw materials are placed in fireproof bricks called boshi and fired.

4. Crushing

The mixture is placed in a machine called a Tron Mill, where it is crushed with water, stones, and gosu.

5. Drying

The gosu crushed in step 4 is dried.

6. Stone grinding

It is ground using a millstone. The final particle size is 1μm (=0.001mm).
It takes about one to two weeks to grind the beans in a stone mill, and the above six steps take more than a month to complete.

Our gosu has the finest grain of any gosu generally sold in Japan, making it ideal for hand-painting.
It is of the highest quality in Japan, and is used by pottery makers who are designated as Living National Treasures or who work for the Imperial Family.

This means there is no need to do any hand-railing once the product arrives .

Furthermore, because we sell directly from the factory, our prices are the lowest you can find on the web.

No adhesive is added, so add the amount you like.
Gum arabic, gum syrup, green tea, etc. are used as adhesives.
However, please be careful not to add too much glue as it will cause shrinkage.

Gosu production video

Please take a look at the video we have put together to show you the process of making gosu at Shinkai Shoten.