What are the artistic features of Zhang Xu's calligraphy?

Zhang Xu, whose date of birth and death is unknown, lived in Xuanzong period of Tang Dynasty. Gao Bo was born in Wu Jun (now Suzhou). At first, he was a governor of Changshu, and later an official, Jin Wu, had a long history (leading the government) and was called Zhang Changshi. Zhang Xu was a heavy drinker and had a dissolute sex life. Huai Su's Zhangdian is one of the Eight Immortals of Drinking. His cursive script, Li Bai's poems and Peiman's sword are collectively called "three musts". Tang people not only created regular script with strict laws and high artistic quality, but also created new cursive script. This kind of cursive script is continuous, like dragon and phoenix dancing, and at the same time it is very organized, so it is called "crazy grass" by later generations. Zhang Xu is the founder of this new cursive script. The difference between Jin people's wild cursive script and cursive script is not only continuous and dynamic, but also the difference in brushwork, that is, it is centered and mostly round, which is different from Jin people's two-sided pen and steep character. Zhang also writes regular script, and his Preface to Langya Stone was once praised as "the first book in Tang Dynasty" by Huang Gu. Yan Zhenqing said that his model essay was written in detail, and he was particularly right. It can be seen that his regular script also reached the peak at that time. Unfortunately, he didn't have absolutely reliable cursive works handed down. But we can see the general appearance of Huai Su's books from his works with similar styles. The four ancient poems handed down from generation to generation are his works. Although there are still different opinions, this book does have the characteristics of his time. In addition, Abdominal Pain Sticker is his work, but it is not his masterpiece.