It has not been polished. Xuande Furnace is a bronze incense burner designed and supervised by Zhu Zhanji, Emperor Xuanzong of Ming Dynasty in the third year of Xuande. Historically, the inner chamber of Xuande furnace was unpolished. The works of incense burners represented by Chen Qiaosheng are all hand-cast, treated with antiques, and restored to the most natural and authentic state of incense burners. Although the unpolished cavity does not look so smooth, it is indeed hand-cast.