육우
A book written by Lu Yu in 618–907 AD (Tang dynasty), "The Classic of Tea" (), is considered important in green tea history. The "Kissa Yojoki" (喫茶養生記 "Book of Tea"), written by Zen priest Eisai in 1211, describes how drinking green tea may affect five vital organs, the shapes of tea plants, flowers and leaves, and how to grow and process tea leaves.