In addition, during the Tang and Song Dynasties, Japan sent a large number of monks and overseas students to China. Many ancient books were handed down in the past, and some of them were handed down through Korea. Many of these books were lost in China, but they were preserved in Japan. Many scholars in the late Qing Dynasty and modern times noticed this and made constant efforts to send these books back to China. As far as I know, there are many medical materia medica, such as Taiyi Xiancao. In addition, there are documents about Dunhuang and Turpan. After Japan, that is, Britain, America and Russia, there are not many fine products, but there are also many treasures. It's a pity that Japan may study our own history better than ourselves. In addition, Japanese ancient scholars edited and transcribed many ancient books in China, many of which were lost in China. Many books can only be glimpsed by editing and copying, such as Danbo Kanglai's "Treating the Heart". There are also books by Lu Xinyuan, a great bibliophile in the late Qing Dynasty, which were later sold to the Japanese by his descendants, including many precious Song editions.