Notes on the Water Mirror is a masterpiece of ancient geography in China written by Li Daoyuan in the Northern Wei Dynasty. Written in 527). The original 40 volumes were lost in the early years of the Northern Song Dynasty, and later generations divided them into 35 volumes to make up 40 volumes. Its writing form is annotation of Shuijing Annotation, a monograph on water system at the end of Han Dynasty. List the main text of Shui Jing Zhu first, and then write the notes. Taking waterway as the key link, it describes the mountains and rivers, lakes, counties, cities, blockades, scenic spots, pavilions, soil, vegetation, climate, hydrology, social economy, folk customs and other aspects that flow through the region, and also records relevant historical stories in various places. The book records more than 300 inscriptions seen by the author as the basis to help determine the water passage. Li Daoyuan noticed the undercurrent at the source of the waterway and there was quite a lot of groundwater under the old canal, and paid great attention to the hydrological changes such as the size of the water source, the depletion of lakes, the turbidity of water color, the accumulation of sediment and the fluctuation of floods. The water mirror only recorded 137 waterways, while the water mirror notes recorded 1252, an increase of more than 8 times. Annotations are about 300,000 words, twice as many as scriptures. It greatly surpassed the water mirror in content and text, and became an unprecedented geographical masterpiece at that time.
Notes on Water Mirror is outstanding not only in China, but also in the world geographical documents at that time. It is a comprehensive summary of the geography of China before the Northern Wei Dynasty, and it also reflects the new progress of the geography of the Northern Wei Dynasty. Zhu is an unusually rich cultural treasure house. Apart from his geographical achievements, he has made outstanding contributions to history, ethnology, archaeology, epigraphy, linguistics and literature.