This is kutani ware, a traditional handcrafted artform famous to Ishikawa prefecture.
It is a special form of pottery that is renowned worldwide for it’s historically significance and beauty.
In this article I would like to explain the process of creating kutani ware from initial conception to completion.
① 採石 quarrying
Kutani ware is made from porcelain stone that is mined in the Hanasaka area of Ishikawa prefecture’s Komatsu city.
This Hanasaka porcelain was first discovered during the latter half of the Edo period.
Hanasaka porcelain stone continues to play a vital role in the production of kutani ware to this day.
② The process of turning porcelain stone into clay.
Clay is created by first pulverizing porcelain stone, and then putting the compound through several processes.
A characteristic of Hanasaka porcelain is it’s high iron-content, so created materials come out gray or often a deeper shade of white. It is also particularly sticky, which is often said to make it easier to form while on the pottery wheel. Through the efforts of recent clay-manufacturers, clay that is more suitable for casting is also being produced.
③ 成形 Molding
This is the process of molding clay into the desired shape. There are several ways this is done.
The picture above depicts the process of molding clay using a pottery wheel. This is the process of forming lumps of clay that are being rotated on the pottery wheel. You can create sake drinking cups, tableware, and pots as well as many various other kinds of items.
・Cast molding by pouring viscous clay into a plaster mold and then shaping. This is often used to create more decorative ornaments, as well as bowls and containers.
・Traditionally the means of molding clay for decorative pieces has been to develop by hand. By crafting each part, pushing and pulling the clay, developing the shape by hand, and finally by pulling everything together for one overall look. This takes a lot of time and effort, so molding by casting has become the mainstream method.
・Hand-pinching or Tebineri is the process of creating smaller workable people, piling them together, and forming them together to create the final shape.
In the case of Tatara molding, clay is made into a flat plate formed with uniform thickness and is then shaped into a square shape.
④ Firing unglazed pottery
Begin by firing the shaped clay.
In the past, firewood was burned in a climbing kiln and baked, but recently gas and electric kilns have become mainstream.
The picture below is a piece of kutani ware known as a Miyayoshi pottery.
The clay is then fired at over 800 degrees Celsius.
The process of firing takes between 6 and 7 hours to complete.
A unglazed vessel taken out of the kiln. The clay will have turned to a subtle reddish brown color.
Glazing is the process of applying an enamel coating to an unglazed piece of pottery.
This enamel is a liquid base that will cover your pottery. The process of glazing must be adjusted depending on the firing temperature as well as the quality of glass you are working with.
It is important to work quickly to achieve an even coat of enamel across the entire piece. It is truly a work of art.
⑥ Firing the glazed pottery
Just as with unglazed clay, pottery used to be fired in a vertical kiln, but recently gas and electric kilns have become mainstream.
The picture below once again shows a Miyayoshi ceramic. The enamel has been applied very precisely.
Glazed pottery must be heated at a higher temperature than unglazed pottery, so the kiln will burn at 1300 degrees Celsius this time.
The firing time will be roughly 12 hours.
When this final firing process is finished, the clay should turn white, and the enamel should be transparent with a shine.
⑦ Final painting and decoration
To start draw outline and pattern lines on the already fired white porcelain with a type of material known as gosu.
* Gosu is a type of pigment containing cobalt, manganese, iron, etc.
↓ The picture below is decorated with gosu and a Japanese red paint.
Kutani were originally decorated with black gosu and what is known as the *wucai style of colors.
The piece has been decorated with gosu and red lines,
so the 4 additional colors of the wucai style were adorned using a traditional Japanese writing utensil.
It is important to be sure to not paint over any previous red lines. This is because overlapping with any previously painted red lines would render them invisible after the firing process.
*Wucai (五彩, “Five colours”, ) is the distinctive color five color palate style of of kutani cermics, made up of cobalt blue, green, yellow, and red. This is a popular motif of kutani design.
⑧ Firing glazed pottery. Final steps to completion.
Fire the pottery one more time at 800-900 degrees Celsius to fix all decorations.
The process of firing will alter the color of light colored paint by making the colors more vibrant.
The four colors of paint will have transformed to a more transparent glass, and the gosu lines under the glass will remain as faint patterns on the pottery.
This transparent look of the enamel is one of the key characteristics of kutani ware.
The production of Kutani ceramics involves the careful division of labor through many different processes such as the creation, molding, and decoration of fired clay. The process of creating one piece of kutani ware is completed by undergoing multiple processes managed by professional level workers with a high level of skill in their craft.
From the experience of firing countless pots, experts gain a sense for exactly the right temperature to set the kiln to. Tools such as glazes, paints, and brushes are also important in achieving a completed product.
All of these parts come together as a whole through each step without a hitch to produce what we know as kutani ware.