Introduction of Baolan: Baolan is also called Jilan and Sacrificial Blue. Jingdezhen kiln was burned in the Yuan Dynasty, and it was tied with red sacrifice and sweet white in the Xuande period of the Ming Dynasty. The blue color of Ji, like the red sacrifice, belongs to high-temperature crystallization glaze. Using cobalt oxide as colorant, glaze is hung on the green body, and then it is fired in a kiln at a high temperature of 1200℃- 1300℃, and the color is stable. During the Kangxi period, there were orange peel, brown eyes and bubbles on the glaze surface of sapphire blue glaze, which were evenly distributed. There are also some glazed surfaces that flow vertically. Kang Yong's blue glaze is an imitation of Xuande in Ming Dynasty, with plates and bowls as imitations. In the early Qianlong period, it was similar to Kang and Yong. Later, it became more refined. But by the end of the Qing Dynasty, there was little blue and the glaze color was not uniform enough.