Among the legendary Five Great Kilns of the Song Dynasty, Jun ware stands out for one reason: color that seems born from accident, fire and magic. At first glance, Jun ware belongs to the celadon family, but it is anything but ordinary. Its basic glaze is a thick, opalescent blue, ranging from pale sky blue to soft moon white. Yet in the kiln, the surface could transform dramatically, blooming with red splashes, purple clouds or rose-colored flashes. That effect came partly from chemistry and partly from chance. Some Jun glazes contained traces of copper oxide. Under the intense heat of the kiln, the glaze underwent kiln transmutation, producing colors that potters could guide but never fully command. The result is porcelain that feels almost cosmic: blue like the sky, red like sunset and purple like clouds catching fire.