Zhang Xusheng was born in the third year of the Tang Dynasty (675) and died in the ninth year of Tianbao in Xuanzong of the Tang Dynasty (750). Then Zhang Xu died in seventy-five. According to Zhang Xu, who was brilliant since childhood, he should be able to grow into a good calligrapher around the age of 25. That is, in the twenty-eighth year of Tang and Shang Yuan (700)?

Note: It is purely personal inference and is for reference only.