China's four rare books are Dunhuang Suicide Notes, Zhao Zang, Si Quan Shu and Yongle Dadian. The four rare books in China are Four Treasures of the Study of the National Library, and the National Library of China has the largest collection of China rare books in the world. Dunhuang suicide note, Zhao Cang, Si Quan Shu and Yongle Dadian are the four collections of the National Library and the treasures of the town hall.