Generally speaking, celadon (青磁 - seiji) refers to high-fired stoneware or porcelain wares covered with a pale, translucent, bluish-green-grey glaze. Typically, these glazes get their colour from small amounts of refined iron fired at high temperature in a reducing atmosphere.

The earliest proto-celadons were developed in the Shang Dynasty in China, but it was only in the Song Dynasty (960-1279) that celadon production became more popular and refined, with Ru, Yue, Yaozhou, Ge, Guan, and Longquan celadons defining the aesthetics of the era. Ranging from pure light blues, to crazed greens, the jade-like ceramic became the standard of the Song Imperial Court.

Celadon from the Longquan kilns (龍泉, pronounced ryūsen in Japanese), was produced in large quantities and exported outside of China. Efforts to mimic these wares in Goryeo Dynasty Korea resulted in a new and unique Korean style of celadon, often with delicate inlay.

In Japan, Longquan celadon was highly regarded, but rarely imitated at first, due to the ceramic technology required. Domestic celadon production only began in Japan in the 1600s.