Notes on Water Classics is a masterpiece of ancient geography in China, with a total of 40 volumes. The author is Li Daoyuan in the late Northern Wei Dynasty. The water mirror annotation is named after the water mirror annotation. The book Water Mirror is about 10,000 words, and the Notes on Six Classics of the Tang Dynasty says that it "draws water from the world, 137". Water Mirror Notes looks like water mirror notes, but in fact, it takes water mirror as the key link and records more than 1000 rivers and related historical sites, stories, myths and legends in detail. It is the most comprehensive and systematic comprehensive geographical work in ancient China. The book also records a large number of stone tablet ink and fishing songs and folk songs, with gorgeous words and beautiful language, which has high literary value. Because many documents quoted in the book were lost in later generations, many materials were preserved. Water Mirror Notes, Notes on the Three Kingdoms (Pei Songzhi), Notes on Shi Shuo Xin Yu (Liu) and Notes on Selected Works (Shan Li) are also called "Four Great Classical Novels Notes".