Painting in iron-brown or copper-red under the celadon glaze was a Korean innovation, of which very few examples have survived. Although underglaze red was used in Chinese porcelain in the fourteenth century, and as early as the Tang dynasty (AD 618–906) on Changsha wares, it was never very successful because it was difficult to ensure a good colour: the copper often turned black during firing. Also, it was not generally used as profusely as here, more typically to pick out details in inlaid celadon ware and overall decoration.
This bowl is decorated with stylized flower scrolls. These scrolls are sometimes called Posanghwa or 'Precious Visage' flowers and are a Buddhist motif. This bowl is a tea bowl and would have possibly been used by Buddhist monks during meditation. Buddhism reached Korea through China and many characteristics of Chinese Buddhism were adopted.