| In the existing materials, there are four letters written by Zhu Yun to Bi Yuan. Two of them are collected in Zhu Yun’s Anthology in Shanghai Library, one is included in The Letters of Collectors in the Ming and Qing Dynasties compiled by Pan Chenghou, and another one is found in the National Central Library in Taipei. A textual research on these four letters can help us understand the relationship between Zhu Yun and Bi Yuan, and the social intercourse between Zhu Yun and his friends and students, like Wang Chang, Chen Songfu, Zhuang Xin，Qian Dian, Qian Chenqun, and Huang Zhongze. As a leading figure of Qianjia School, Zhu Yun made a great effort to guide and support his students. |
