The Chashu 茶疏 "Comments on Tea" is a book on tea compiled by the Ming period 明 (1368-1644) scholar Xu Cishu 許次紓, courtesy name Xu Ranming 許然明. He came from Qiantang 錢塘 (modern Hangzhou 杭州, Zhejiang), but not much is known about his life. His short book Chashu is divided into 39 chapters that explain methods of harvesting tea, their storage and preparation method. Although the Chashu focuses on these few points, the descriptions are very detailed. There is one crucial mistake in the text concerning the well on Mt. Jinshan 金山. The book was owned by the library of the Imperial household (neiwufu 内務府). It is included in the collectanea Baichuan xuehai 百川學海, Chongding Xinshangbian 重訂欣賞編, Shuofu 說郛 and Gujin shuobu congshu 古今說部叢書.
Source: Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, vol. 2, p. 1863. Changchun: Jilin daxue chubanshe.