When we talk about a Calligraphy Monk, Zhiyong was definitely the first one we would think of. Zhiyong's position in the history of the Chinese calligraphy is certainly undisputed. However, to some people, Huaisu's calligraphy, especially his cursive hand (caoshu) is more appealing. To a great extent, Huaisu is considered to be one of the best in the category of the cursive hand in the Chinese calligraphy, In this respect, it would be appropriate to say that there is yet another Calligraphy Monk, Huaisu.

Huaisu (725-785) came from a Qian family Zhangsha of Hunan Province. His father Qianqi was a famous poet (one of the Ten Greatest Witty Scholars during the Dali reign). Huaisu's other name was Zangzhen.

Huaisu became a monk during his childhood and was a student of his uncle, the Master Huirong (a monk as well). Master Huirong was very obsessed with calligraphy too, especially with the calligraphy of the great Tang Dynasty calligrapher Ou Yangxun and spent much time in imitating Ou's calligraphy. Master Huirong's imitation got so good that very few people could differentiate it from the original by Ou. It's very likely that Huaisu inherited such great inclination towards calligraphy from his uncle.

In the year 762 during the reign of the Emperor Suzong of the Tang Dynasty, he was asked by the emperor to stay in the Western Taiyuan Temple.

In the history of the Chinese calligraphy, Zhang Xu was by far the greatest in the category of the wild cursive hand. After Zhang Xu, most people would consider Huaisu as the successor in wild cursive hand. People like to put Zhang Xu and Husaisu together in saying "The crazy Zhang and the wild Su".

Huaisu studied calligraphy from the great Tang Dynasty calligrapher Yan Zhenqing and learned the brush styles of Zhang Xu from Yan. In this way, Huaisu inherited and developed the cursive hand innovation started by Zhang Xu and made a very significant contribution in the history of the Chinese calligraphy.