The strong bulging curve from the shoulder toward the base represents a development in the handling of the potter's wheel. The short neck rises vertically and the rim is slightly chipped. The short foot is shaped a little wider at the bottom, and is considerably chipped. In the Sanage kilns located in the southwestern outskirts of Mt. Sanage in Aichi Prefecture, sue ware (unglazed pottery) had been widely produced, but under the influence of celadon porcelain brought to Japan from Yueh-chouyao in China, this ware was gradually replaced by the ash-glazed ware of the early 9th century. In the 10th century, skill in handling a potter's wheel and ash glaze meant further progress. This vase, with a green-tinged ash glaze, must have been produced around that time.