Otani-yaki is characterized by its unique technique and texture
Otani-yaki (Otani ware) is a type of pottery produced mainly in Naruto City, Tokushima Prefecture. Dark brown Otani-yaki is the most common color, but shades of gray and deep silver are also popular. Every November, the “Pottery Market and Otani-yaki Kiln Festival” takes place in the precincts of Torinin Temple, and hosts a large number of people with pottery lovers and local people. Otani Pottery is also famous for the “Neirokuro” method of pottery making. The process, in which an assistant lies down under the workbench and turns the wheel with his/her feet, is not seen anywhere else. The “Noborigama” kiln is the largest in Japan and produces a large number of large ceramics.
The production method of Otani Pottery is unique and unparalleled in other regions. The “bedding wheel” is instinctive method to make large jars and other large ceramics that are as tall as the wearers. An assistant lies down under the workbench and turns the wheel by kicking it with his/her feet. The “climbing kiln,” in which the items formed by the reclined wheel are fired, is also famous for as the largest of its kind in Japan. The pottery finished by sophisticated rokuro techniques and baking kilns is thin but extremely sturdy. This makes it popular as tableware such as yunomi (teacups) and chawan (tea bowls).
In addition, the Otani clay used for this traditional craft has a high iron content, giving it a rough texture and a faint metallic luster. Otani Pottery, with its simple yet somehow graceful glow, has been attracting attention from overseas as well. Some visitors come all the way to Tokushima Prefecture after falling in love at first sight with Otani-yaki featured in the foreign media.
History of Otani-yaki
The origin of Otani Pottery dates back to the Edo period (1603-1868), when Bun’emon, a pottery craftsman from Bungo Province (Oita Prefecture), made a pilgrimage to 88 sacred sites on Shikoku Island in 1780 and fired pottery in Otani Village using red clay from Kanigaya and a potter’s wheel.
Haruaki Hachisuka, then lord of the Tokushima domain in Awa province, took an interest in ceramics, and in 1781, he built a domain-owned kiln in Oya village, giving birth to the first dyed porcelain in Awa province. Although many craftsmen flowed into from Kyushu to produce Otani ware, the kiln came to the end after only three years due to unprofitability of the raw materials that had to be imported.
Later, however, an indigo merchant named Kaya Bungoro (Kasai Sozaemon) met Shigaraki potter Chuzo, and the road to reviving Otani ware began to open. Kaya Bungoro brought Chuzo back home and had his younger brother Heijihei teach him the techniques, and in 1784, a private climbing kiln, the renbou style climbing kiln, was built in the town of Oama, Naruto City. A new history of Otani-yaki began.
 |
| Source: https://www.awanavi.jp/spot/21692.html |
Manufacturing Method and Process
There are two methods of Otani-yaki production.
- Wet process: dried clay is crushed and sieved while stirred in a water tank
- Dry: dried clay is crushed, sieved, and kneaded with water.
Wet type for Otani-yaki
1. raw clay
Mainstream Hagiwara clay gets mixed with clay from other prefectures to improve fire resistance.
2. crushing
Dry The raw clay and crush. Takes at least one week at the most.
3. water-sieving
Stir the clay in a water tank and sieve, and scraped off the precipitated clay.
4. Kneading
Kneading to remove air from the clay removed by water-sieving.
5. Molding
Form the clay by using a potter’s wheel. This is where the traditional Oya-yaki potter’s wheel is used.
6. Drying
Dry the formed clay for two days to a week.
7. unglazed
Firing in a furnace at around 800 degrees Celsius for 7 to 8 hours.
8. Glazing
Pouring and dipping to form Various glazes by using craftmanship techniques.
9. Main firing
Firing at 1300 degrees Celsius for 12 to 24 hours using a climbing kiln, electric kiln, or gas kiln.
10. Finished products
After firing, remove the pieces from the kiln after cooling for 2 or 3 days. Finally, Inspection.
Dry process for Otani-yaki
1. Sifting
Mix The raw clay into dry powder.
2. Mixing
Add Water to the dry powder and mix.
3. Kneading
Kneading The clay and divide into pieces according to the size of the product. A clay kneader is sometimes used.
4. Molding
Molding the cray with an electric wheel, kick wheel, or bed wheel.
5. Glazing
Glaze evenly with a ladle. Glazing when the clay is still in the raw stage, before it dries.
6. Drying
Dry in the shade indoors for 20 days and then dry in the sun.
7. Kiln Filling
Large pieces are stacked naked, and small pieces are placed in the gaps. Smaller pieces are stacked or shelved.
8. Firing
In the case of a climbing kiln, firing takes about 5 to 6 days and nights. In the case of an electric or gas kiln, firing takes about 1 day and night at 1,300°C.
9. Finished products
Cooling for 7 to 10 days before unloading the kiln.
 |
| Source: Mapple Travel guide |
The following is the manufacturing process of Oya-yaki in general. That gives a detailed explanation of each process, but it is insufficient in two respects: strictly speaking, there are two processes, and the explanation is for the general terms without classifying them correctly. Kogei Japan, one of the largest English-language providers of information on traditional Japanese crafts, also uses this method, but I must say that it is inadequate when asked for accurate information. However, it can be used as a reference to learn the details of the process.
General Process
1. Pulverization
Collect The raw soil , dry, and crush into small pieces.
2. Sifting
Passing the Crushed soil through a sieve to remove impurities and refine it.
3. Sieving
Place the purified soil in a water tank and stir. While stirring, the soil gradually goes the next step by pouring into another tank at the same time. After the transfer is complete, remove impurities and the clay, the raw material of ceramics, is left to settle for a while. Then, put the settled clay into a mortar bowl and leave until it becomes the proper consistency.
4. Kneading
The potter kneads the clay with his bare feet on top of the circularly spread out clay, using both feet to push and stomp the clay to make it uniformly soft. Next, the craftsman kneads the clay with his hands to remove air bubbles from the clay while rotating it after the rough kneading process.
5. Molding
Transfer The clay to a potter’s wheel and molded by hand.
For large ceramics, the traditional molding technique of Otani Pottery, called “Nerokuro,” is used, where two craftsmen work in pairs to form the clay into a shape.
6. Drying
After forming, dry the products indoors in the shade. For large ceramics such as jars and bowls, dry the products in the shade for about 20 days. For smaller ceramics, leaving in the shade takes from 2 to 7 days. Next, move them outdoors to dry in the sun. For large ceramics, it takes about 2 or 3 days, and for small ceramics, about 1 day.
7. Glazing
After drying in the sun, the potter moves on to the glazing process. There are three main methods of applying glaze. The first method is to apply glaze without unglazing, known as nama-gake. Other methods include dipping, in which dipping the unglazed pieces, and pouring; in which pour the glaze over the pieces using a ladle. Completing “Unglazing” in a kiln at approximately 800 degrees Celsius for 8 to 16 hours.
8. Kiln Filling
Put the products in the kiln for firing.
9. Firing
The temperature of the kiln reaches approximately 1,230 degrees Celsius, and firing the products in the temperature. There are three types of kilns: climbing kilns, electric kilns, and gas kilns. In a climbing kiln, 5 to 6 days and nights are necessary, and in an electric or gas kiln, 1 to 2 days.
10. Inspection
Remove the products from the kiln and checked for chips, cracks, etc.
11. Completion
Only products that have passed inspection are selling products.
