At that time, the blue pigment was imported from the Middle East, because it emerged more brilliantly than was possible with the rather muddy Chinese cobalt.
在煉燒陶瓷藝品時，因為意外的因素，例如火溫、顏料的分量、釉的成分發生意外的突變時，所燒出的成品可能是一無價值的壞品，也可能產生可遇而不可求的「窯變」作品。