Extracting the Clay: Clay suitable for making pottery is extracted from the mountains around Agano, and it is the job of a very experienced potter to go out and look for good quality material. The extracted clay is then dried.
Pulverizing: The clay is finely broken up by machine at the workshop. The fine clay is then put through a sieve to separate off the best clay and the bigger pieces of clay and dirt which are left behind, are discarded.
Straining: The good quality clay is now mixed with water in a tank. By filtering the water once more it is possible to strain off a fine enough clay for production. The clay is sucked up by machine and then after the water has been squeezed out, it is partially dried.
Pugging: With the clay made into a square lump, it is then put through a pug mill to make it into cylindrical lumps.
Wedging: After the clay has been allowed to weather, it is thoroughly wedged by hand to rid it of any air. It is very heavy work and to do it well takes a great deal of experience.
Forming: The wedged clay is centered on a wheel and then freely formed by an experienced potter. When forming is complete, the shape is perfected using various tools.
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Drying, Finishing: The pieces are first dried to make them leather hard, after which they are trimmed and finished. Then they are allowed to dry for several days.
Glazing: When the pieces are thoroughly dry, they are biscuit fired. This makes it much easier to apply overglazes and improves the adhesion of the color during the main firing. Pieces are tightly loaded into the kiln and fired for between five to six hours at a temperature of between 800°C and 850°C. Even if pieces are successfully fired, they may be smashed if they do not meet with the approval of the potter.
Glazing: Those pieces which have passed inspection are now glazed. The glaze itself is made from such materials as the ash from straw, or an iron oxide rich soil from the mountains. The glaze vitrifies and covers the piece with a glass-like membrane and takes on a beautiful coloring. The potters of Agano talk of the magic which seems to occur when pieces are fired and the clay and glaze takes on a new guise.
Main Firing: With everything ready, the main firing can begin. The kilns used are either fired with wood or gas. Firing with gas lasts about ten hours. The whole process from extraction of the clay to firing the kiln takes several days but all the hard work is rewarded with some fine pieces of pottery.