Zhang Xu, born in the third year of Shangyuan of Tang Dynasty (675) and died in the ninth year of Tianbao of Xuanzong (750), was born in Wujun (Suzhou, Jiangsu). He first served as a captain of Changshu, and later he became a long-time official in Jinwu, and was known as "Zhang Changshi." He was skilled in poetry and calligraphy, and he was familiar with regular script, and he was most famous for his cursive script. He was free and uninhibited, open-minded and unrestrained, and was fond of drinking. He was known as the "Eight Immortals of Drinking" together with Li Bai, He Zhizhang, Li Shizhi, Li Jin, Cui Zongzhi, Su Jin and Jiao Sui. When he was drunk, he would wet his hair with ink and write big books. He was so drunk that he was called "Zhang Dian". At that time, Li Bai's poems and Pei Wen's sword dance were called "Three Wonders". His calligraphy was obtained from the two kings and is original and creative. His calligraphy includes "Lang Guan Shi Ji", "Four Posts on You Shi in Cursive Script", etc. His main book, "The Story of Lang Guan Shi", is completely written by Yu Ou, which is strict and regular. Ouyang Xiu's "Collection of Ancient Records" said: "Xu is famous for his cursive script, and "The Story of Lang Guan Stone" is in real regular script and lovely." "Four Posts on Ancient Poems" With its new and noble form, the huge soul unfolds the majestic scroll. Feng Daosheng's postscript: "The writing is as if it were thrown from the sky, elegant and smooth, shining like the light of the sky, if it were not done by human hands." "Xuanhe Shupu" said: "Although his cursive characters are full of strange characters, but looking for their origin, there is no trace of painting. Those who should not behave themselves."
Huaisu (624-697), Shi Huaisu, whose common surname was Fan, was a disciple of monk Xuanzang and the founder of the Dongta Vinaya Sect. His cursive writing is thin and vigorous, and moves naturally, like a sudden rain and whirlwind, changing at every turn. Although his calligraphy is free-spirited and ever-changing, it is still lawful. Huaisu and Zhang Xu formed a situation where the two peaks of calligraphy in the Tang Dynasty stood side by side, and they were also two unattainable peaks in the history of Chinese cursive calligraphy. Handwritten calligraphy handed down from ancient times include "Autobiography Tie", "Bitter Bamboo Shoots Tie", "Eating Fish Tie", "Notre Dame Tie", "Lun Shu Tie", "Dacao Qianwen" and "Xiaocao Qianwen".