Stoneware is a hard high-fired ceramic made from coarse clay. In Korea stonewares were first produced during the Three Kingdoms period and until the 9th century AD they constituted the majority of ceramics on the Korean peninsula. Korean stonewares are amongst the earliest known high-fired wares in the world. They were fired at temperatures of more than 1000° Celsius. As a result of the firing they are normally grey in colour. Such high-fired stonewares were used for storing liquids and food. They were also used as burial gifts.

In the late Three Kingdoms period potters began glazing the wares. At first the glaze was not intentional. It happened by accident during the firing when ash circulated through the kiln and stuck to the surface of the vessel. Such ‘accidental glazes’ can be recognised by their thin and uneven appearance. Later the potters covered the stonewares with ash before placing them in the kiln, resulting in smoother surface.

Distinct local characteristics can be seen in the wares. In the Kaya region vessels of unusual sculptural shapes were made. In Silla vessels were sometimes decorated with individual figurines and small clay models which might have been used to avert evil.