The time-consuming technique of inlay in celadon ware (sanggam) involves incising or carving the design into the unbaked, leather-hard clay with a needle or wooden tool and filling in the resulting depressions with a white or black substance. The piece is given a biscuit or first firing, then coated with a celadon glaze and fired again at a higher temperature. Although inlaid decoration was used in Chinese ceramics during the Tang (618?907) and Northern Song (960?1127) dynasties, it was not widespread and its application to celadon ware was never fully exploited. Among makers of Koryô celadon, however, it became a favored decorative technique, establishing a distinct and important category of Korean ceramics.
The decoration of this small bottle is a rare example of the technique of reverse inlay. The area around the design is carved away and the background then inlaid with a white substance, which, when the piece is glazed and fired, produces a green pattern against a cream-colored ground.