Jun Ware

Jun ware is most easily identified by its thick, opalescent blue-to-violet glaze, often featuring striking splashes of purple or crimson. The glaze typically features a network of fine cracks, known as "crazing," that developed during the cooling process. This distinct visual effect was achieved by incorporating copper oxide into the glaze recipe.

This type of stoneware was primarily produced in Henan Province during the Song and Jin dynasties. The kilns were heavily active between the 11th and 15th centuries. Imperial kilns at Juntai were eventually established to produce wares exclusively for the royal court.

The distinct purple and blue hues in Jun ware were achieved through a reduction firing process involving a copper-rich pigment. As the copper interacts with the fire and oxygen levels in the kiln, it creates unpredictable flashes of color. This technique was revolutionary, as copper was previously used mostly for green lead glazes.

Opalescence refers to the milky, blue-ish visual effect seen when light reflects off the microscopic glass particles within the glaze. This is caused by liquid-liquid phase separation that occurs during the high-temperature firing process. It gives the pottery a smooth, glassy surface that almost glows from within.