A network of irregular cracks in the glaze caused by a disagreement in the rate of shrinkage between body and glaze during cooling. From the Song dynasty and onwards crackles seems to have been intentionally produced as decoration. The appearance could be enhanced by tea (red) or ink (black) being rubbed into the cracks. Crackle decoration is to be found on such Sung dynasty wares as Ru, Guan, and Ge , or on archaizing wares made later, up until today. Traditionally the Chinese connoisseurs have been distinguishing between a large, bold, crackle, termed "crab's claw", and a much closer and smaller network termed "fish roe" crackle. The former developed first, and was accentuated with black pigment: the latter, developing at a later stage, was coloured red. On Ge ware sometimes a combination of both are found. Crazing of the glaze of some excavated wares might not be intentional, but the result of burial. Crackled porcelain typically also occur as a defect when the ceramic piece is not fired at high enough temperature, but remains somewhat soft. A dull sound - no ring - when a dish is tapped plus crackles clearly points at it being somewhat underfired. See also crack and break.