It is put in a wood burning kiln unglazed but acquires a natural ash glaze and subdued shadings from the 10-15 days long firing. The finished product is simple and quiet with the feeling of the clay being presented very directly. This does not happen by chance. The process is painstaking. Clay taken from the rice paddies or mountain must be put through many processes over a long period of time climaxing with it being touched by flames as temperatures of around 1250°C / 2282°F are reached. That's why Bizen ware is known as the art of Earth& Fire, and the beauty of Bizen ware is thought to be born from the union of nature and man.
The long wood firing creates a variety of interesting surface colors and ash coatings. The variations have names and can also be seen on very old examples of Bizen ware. Consistent results require long experience and great knowledge of the kiln and firing. The kiln loading and firing techniques have been handed down and refined from generation to generation. Some techniques have been lost over hundreds of years, and recently, new techniques are being developed by individual potters. Some of the main factors which influence the color and texture of the surface of the ware include: temperature, place in kiln, moisture (water vapor) inside kiln, atmosphere (oxidizing or reducing), type of wood used in firing, length of firing, type and size of kiln, etc.
Clay is obtained from the rice fields in Inbe, usually during the season when rice is not being grown. The clay lies from 1 to 3 meters below the surface in layers about 20 to 40 centimeters thick. It is transported to the potter's workshop and is commonly kept under a roof where it will dry and not be washed away by rain. Then, small (approximately 23cm) sections of clay are examined, which typically exhibit the marbling of smooth chocolaty blackish sections, very fine sand and clay grayish sections, and more coarse rocky sections.
The clay is aged for a few weeks to months after adding water, and then it is formed into various shapes.
Red pine permits high temperature so it is appropriate for Bizen ware, and is also necessary for the distinctive surface variations. 7t ~ 8t pinewood is needed for one firing.
Bizen ware is fired from about 7 to 14 days at about 1250 degrees. The fire must be watched constantly day and night.
Immediate remove from the kiln would crack Bizen ware because of the sudden change in temperature. The kiln must be left to cool, for about one week before opening.
Bizen ware is mainly produced in Inbe, located in Bizen City, Okayama Prefecture in western Japan. Bizen ware is regarded as one of the six ancient kilns representing Japan.The history has been for approximately 1000 years.The fertile rice fields, great climate and rich forest firewood resources in Inbe have contributed to the development of Bizen ware.