Introduction to the "Three Fans": The "Three Fans" are the brothers Fan Weizeng, Fan Shaozeng, Fan Xizeng and their grandfather Fan Mian. They are called the "Three Fans of Huaiyin". All three of them studied diligently and excelled academically. They were successful in their careers and wrote many books. Fan Xizeng, in particular, had read extensively and made up for the mistakes of his predecessors, making contributions to the past and future of ancient bibliography.