English: Tamba was one of the "six old kilns" of Japan, where for centuries utilitarian storage-jars were produced for use in rural areas. These storage-jars eventually came to be admired for their aesthetic qualities. They were fired for long periods of time; wood ash repeatedly blew in from the firing box, settled on the jars, and then reacted with the clay body or the glaze of the vessels. The result was an object that-- with its many layers of glaze --seemed to be the result of natural processes. This little jar, attributed to the Yamauchi kiln in Tamba, combines good planning with mishap and chance. The jar was first formed on the potter's wheel and cut off at the bottom with a cord, leaving on the untrimmed foot a whorl design like an oversized thumb print. Then it was dipped into a glaze, some of which was wiped off by the potter when it ran onto the lower part of the body and the foot. The potter's fingers did not create walls of uniform thickness; where the glaze accumulated it fired darker, due to the concentrations of iron oxide, resulting in horizontal striations. Falling ash and temperature differences in the kiln also had an effect: when the iron oxide in the glaze reacted with lime, present in high amounts in wood ash, it turned yellow rather than brown.