A type of ceramics in ash glaze which includes a small content of iron, called celadon glaze. With high temperature of over 1,200 degree through reduction firing, the color varies from blue to green. Its delicate tones depend on the blending ratio of iron and methods for firing. Originated in ancient China, celadon ware washighly regarded as prestigious ceramics which expresses the color of Jade. Later, it was spread to Korea, Southeast Asia and Japan. Celadon wares in powder blue (粉青 – funsei) produced in China during the Southern Song Dynasty were especially cherished as the highest-ranked masterpieces in Japan. Its literal name is sometimes distinguished in Chinese character by its materials, when using stones it is referred to as “青磁 – seiji”, and when using clay it is referred to as “青瓷 – seiji”.