A coppery green ceramic glaze. Since iron oxide made by firing green (iron sulfate) was used for red glaze in Hizen (Saga and Nagasaki prefectures) since ancient times, it is assumed that the first copper green glaze was also made from chalcopyrite (copper sulfate), but copper shavings were used in later periods. Modern blue oribe glazes also use copper shavings (brass powder) and hege (the oxidized product of copper sheet production by craftsmen). Aside from the soft glaze used in Tempyo-yuji porcelain, copper green glaze for hard ware was probably introduced from Korea to Karatsu during the Azuchi-Momoyama period, then to the Mino Kushiri area (Izumi-cho, Toki City, Gifu Prefecture), followed by its spread to the Seto area. In Seto and Mino Seto kilns, chalcopyrite glaze was added to yellow Seto, then to Oribe glaze, and finally to earthenware Aoryu glaze (Seto’s so-called Ueno glaze). In terms of the history of the development of the mining industry in Japan, the art of mining and metallurgy declined greatly between the Heian and Kamakura periods and the Muromachi period (1336-1573), but copper production gradually flourished during the Azuchi-Momoyama period (1573-1573). In the Edo period (1603-1867), even after the ban on the export of gold and silver, only copper was allowed to be exported. This is reflected in the products of Seto ceramic kilns, where copper glaze was not used at all in ancient times, and copper-green spots appeared on the surface of Kizeto glaze at the same time as Ayame-te Kizeto ware was produced, which is thought to have been produced in the Azuchi-Momoyama period. At first, copper was regarded as precious and only a few spots were applied, but as copper production increased, copper was used in large quantities, and Oribe vessels were covered with copper-green glaze on half or all surfaces.
