I use two kinds of clay: Hagi and Bear River . When I opened my studio in Tochigi Prefecture Kuroiso, I would do what most potters do when they need more clay or glazing materials-pick up the phone and order it. Nowadays it not quite so simple.
I go out with a spade to dig up most of my clay for myself. I prepare all my own ashes from rice husks, rice stalks and various kinds of wood (cherry, oak, pine and cedar) that I burn in the winter in my stove. I sometimes go to the local mountains and get volcanic ash, which I use extensively in my glazes.

Another valuable source of materials is neighbours. A very helpful bunch of people, they often turn up at the door with unusual kinds of clay and other materials. It can be very exciting to use them, as I am never really sure what they may be or what results I might get.


The Bear River clay is the most difficult to use. Working with it on the wheel soon after digging it is impossible. First I have to clean it and get rid of the stones, then leave it for at least a year to sour. Mixing in a good measure of beer helps speed the process. The ashes are never quite the same from one batch to another, as different proportions of wood and bark produce a different result. I always have to test them to try to find the best result.


This time I have used ash and zinc crystalline glazes. A majority of the work has been fired twice, though those incorporating glass or gold have been fired three or four times. Most of the effects are a product of chance and very much one of a kind .In the end the kiln has the final word.

I hope you enjoy the results.


Technical Notes

The ash glazes I use are known as Chun or Jun, copper red ash glazes that were used by the Chinese of the Sung Dynasty, from the 11th to 13th centuries. Nobody is quite sure of the composition of the glazes back then. I do a reduction firing to about 1260 C. By using various blends of ashes I can get different tones of blue, red and purple.


The crystalline zinc glazes owe a lot to intensive experiments by German scientists in the 1920. To produce large crystals they sometimes fired a piece for over a month. I do an oxidization firing to about 1300C. During the cooling I hold it at one temperature for up to 5 hours. I am never sure how the crystals may turn out. I might get just a few big crystals or lots of small ones.

Jay Jago
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