Celadon (seiji)
Japanese and East Asian ceramic ware with a distinctive blue-green glaze derived from iron oxide. Celadon (seiji) arrived in Japan from China and Korea and has been produced in Japanese pottery regions including Hasami and Arita. The quiet, jade-like glaze suits the wabi aesthetic.
FAQ regarding Celadon (Seiji)
Q1. What kind of technique is "Celadon" (Seiji), and how does it achieve its beautiful blue-green color?
Celadon is a traditional pottery technique that achieves its unique blue-green or jade-like color by applying an iron-rich glaze (celadon glaze) onto the clay body and firing it at high temperatures under "reduction firing"—a process where oxygen inside the kiln is strictly restricted.
Before firing, the glaze looks like ordinary gray or brown mud. However, when the kiln atmosphere deprives the trace amounts of iron within the clay and glaze of oxygen (reducing it), it dramatically transforms into a mystical blue or green. This art reached its historical peak during China’s Song Dynasty, where potters sought to replicate the prized look of jade. In Japan, highly prestigious celadon continues to be crafted today in celebrated styles such as Arita ware (Saga Prefecture), Kiyomizu ware (Kyoto Prefecture), and Nabeshima ware.
Q2. Why do some celadon pieces look crystal clear while others feature intricate crackle patterns?
The appearance of celadon changes dramatically depending on three key factors: the color of the underlying clay, the thickness of the glaze, and the presence of crackle patterns known as Kannyu.
When a clear celadon glaze is applied thinly over a pure white porcelain body, it creates a crisp, translucent appearance reminiscent of a serene lake surface (often called Seihakuji or pale blue celadon). On the other hand, when a thick, viscous glaze is layered multiple times over a dark, iron-rich stoneware clay, it yields a deep, buttery, and opaque jade-green (classic celadon blue). Furthermore, the web of cracks that forms in the glass layer during cooling—caused by the different shrinkage rates between the clay and the glaze—is called Kannyu. Intentionally staining these cracks with ink to highlight beautiful, spiderweb-like geometric patterns is a highly revered style inspired by ancient imperial kiln wares.