Emperor Zhu Pi introduced: There were four Jiangning weavers in the three generations of the Cao family where Cao Xueqin lived. In the 43rd year of Emperor Kangxi's reign in the Qing Dynasty (AD 1704), Cao Yinxie, a weaving doctor in Jiangning, appointed him to inspect the salt and folded it with the date of his appointment. There is also a seal written by Emperor Kangxi Zhu on it.