"The Eighty-one Difficulties of the Yellow Emperor's Internal Medicine" is a classical theory book of traditional Chinese medicine written by a native of Qinyue (Bian Que) during the Warring States Period. The "Nanjing of the Yellow Emperor" has a total of eighty-one difficulties, which respectively discuss medical contents such as pulseology, meridians, hidden images, diseases, acupoints, and treatments. It is a supplement and elucidation of the relevant contents of the "Nei Jing". "Difficult Classic" is not only the development of pulse theory in "Huangdi Neijing", but also laid the foundation for the formation of Zhongjing's clinical flat pulse syndrome differentiation system.
