During the Kamakura Period (1185-1336 CE) and Muromachi Period (1336-1568 CE) we see the rise of the 6 Ancient Kilns (Seto, Bizen, Tamba, Shigaraki, Echizen, and Tokonome). These are place names referring to the sites of these pottery making villages. The earliest examples from all these kilns are very similar, featuring coarse, heavily thrown, ash glazed storage vessels made of stoneware. This example from Tachikui, one of the Tamba sites, is representative. Tamba is the name of an old province in Central Japan, a mountainous regions through which an ancient highway passed. This storage jar in stoneware shows random accumulations of ash from the firing in the anagama (hole) kiln. These tunnel kilns were excavated into sloping hillsides and took advantage of the natural updraft. At the high temperatures reached in these kilns (above 2300° F.), the wood ash that would be circulating in the air drafts in the kiln acts as a flux on the clay surface, causing the clay to melt and form glaze. These accumulations would be uneven, and often be concentrated on the side of the vessel facing the draft, as can be seen here. As the ash deposits continue, the glaze builds up thicker, and begins to flow down the sides of the vessel. Ash glazes are of muted color, reflecting the color of the clay from which they were formed. Such a natural ash glaze is called bidoro. The granules that can be seen in the glaze at the shoulder are pieces of the kiln roof that fell into the glaze during the firing process. Forms such as this were used to store seeds, and used for pickling.
The use of tunnel kilns, stoneware clays, and natural ash glazes was first seen in China of course. The Japanese believe that Chinese techniques came to their island because of a potter named Toshiro. He is said to have visited China in 1223 in the company of a Buddhist monk, Dogen, who wanted to study Zen meditation at a Chinese monastery. Toshiro went along to study pottery making at a nearby kiln. Toshiro returned to Japan in 1228, and set up a kiln at Seto, and began to make pottery in the Chinese style. From here, the use of tunnel kilns, stoneware clays, and ash glazes spread to the other Ancient Kiln sites, such as Tamba.
TAMBA STORAGE VESSEL, JAPAN, 18" height,
Ash Glazed Stoneware, 1200-1300 CE
