2. Zhang Xu was born in a family with high family background. He studied calligraphy under his cousin Lu Yanyuan, and was highly praised by Wu Daozi and Yan Zhenqing after his success. When he was old, he was promoted or recommended, recruited talents, entered the official position, and was released as a captain of Changshu County. He has served as the left governor and the governor, so he is called "Zhang Changshi" by the world; He died in the second year of Gan Yuan (759) at the age of 75.
3. In calligraphy, Zhang is good at observing objective things and combining objective natural images with personal subjective feelings. He not only inherits tradition, but also dares to innovate. By inheriting and innovating the calligraphy achievements of predecessors, his own weed art reached a peak in the prosperous Tang Dynasty.
4. In calligraphy, Zhang Xu advocated the idea of learning from nature and emphasized seeking inspiration from nature and human social life. In Zhang Xu's eyes, all natural images and all traces of life are the objects of learning from nature, which can inspire his creative inspiration. According to historical records, Zhang Xu enriched the thought of cloth and white structure from "contending for Tao", got inspiration from "Wen Yiduo" for the speed, weight, Ji Xu and thickness of brushwork, and found the compact, powerful, reasonable and erratic charm of wild grass calligraphy from "sword dance", which made the calligraphy have a qualitative change. From these records, we can know that Zhang is good at observing objective things. With the eyes of a real artist, Zhang Xu searched for symbols corresponding to his emotions and personality in nature and life, integrated the situation of all things in the world with his subjective modality, painted wantonly, and used techniques as the means of spiritual expression, thus turning everything in technology into Tao and everything into his own artistic language, and finally formed the expression form and style of Wild Grass flying wildly.