Huai Su (737 ~ 799), known as the “sage of grass” in history, was an outstanding calligrapher in the Tang Dynasty. The word zangzhen, the monk’s name is Huai Su, the common surname is Qian, the Han nationality, from Lingling, Yongzhou (Hunan). He is the nephew of Qian Qi, one of the ten talents of Dali. Huai Su became a monk since he was a child. During the time of Zen, he devoted himself to cursive calligraphy, which is as famous as Zhang Xu and is collectively known as “Dian Zhang Kuang Su”, forming a situation of two peaks of calligraphy in the Tang Dynasty. It is also two peaks in the history of cursive calligraphy in China. Huai Su’s cursive script is thin and vigorous. It flies naturally, like a shower and whirlwind. It changes with your hand. Calligraphy is easy and changeable, and has the method. The handed down works include the autobiography, the paper version of the thousand character essay on grass, the bitter bamboo shoot, the virgin and the treatise on books.