The technological basis for the visual appearance of Koryo Dynasty inlaid celadons is examined and compared with that used in Chinese celadon production. Korean potters worked with raw materials of a more limited composition and a smaller kiln design than Chinese potters, and they developed a way of producing the desired jade-like translucency in green glazes which is entirely different than any of the mechanisms used by Chinese potters. This and other Korean contributions to celadon technology are described. Even though the composition of Korean celadon glazes stayed essentially the same from the 11th to the 15th century, the technology was altered to meet new market and economic demands. Korean green-glazes wares changed from molded, incised and plain celadon (Ch'ongja) to inlaid celadon (Sanggam Ch'ongja) and finally to Punch'ong wares which have inlays set into stamped or rolled impressed patterns. This change is outlined.