Liu Ti refers to Liu Gongquan (778-865), the last great calligrapher in the Tang Dynasty and one of the four masters of regular script. Liu's body is balanced, thin and hard, chasing Weibei steadily, with smooth and beautiful stippling, thick bones and tight body. "Books are expensive, thin and hard, and the spirit is clear." Compared with his face, his regular script is slightly flat and thin, so it is called "Yan Gu".