Caoshu (cursive hand) is characterized by sketchy, simplified forms of characters, often distorted or exaggerated to achieve an internal rhythmic appearance within the compositions of characters. In theory, any character can be written in the style of Caoshu, for instance many course characters appeared in inscriptions on bronze wares. However, Caoshu in literature refers to a specific style developed from Qin Li (official script in the Qin Dynasty), formed around the Western Han Dynasty (206BC-8AD) and prevalent in the Eastern Han Dynasty (25-220).

"Gushi Tie" by Zhang Xu
Historical records show that Caoshu came into being in the pre-Qin period due to the fact that the fierce competition among various states made them often keep alert of any move of other states, which put a high demand on the communication

"Zixu Tie" by Huai Su
Caoshu in the early period retained much feature of Lishu and was called Zhangcao (a coarse style formed by breaking up the forms of Lishu). From the Eastern Han Dynasty (25-220) to the Wei (220-265) and Jin (265-420) dynasties, Caoshu got rid of the trace of Lishu strokes, and employed a large number of running strokes, and was called Jincao (the modern cursive hand). By the Tang Dynasty (618-907), Caoshu developed further, was written in a lively and vigorous way and was called Kuangcao (crazy cursive hand).

Because Caoshu uses lots of running strokes and only has the outline of the characters, it is illegible to most readers and affects its function of communication. Therefore, though Caoshu came into being comparatively early, it didn't become in written form within a state, while Zhuanshu (seal script) and Lishu (official script) could not be written hastily, hence Caoshu emerged. one of the calligraphies in general use. However, it has been always loved by many people. Famous Caoshu calligraphers include Zhang Zhi, Zhang Xu, Huai Su and so on.