Yan Zhenqing and Liu Gongquan. Through "Calligraphy Stories: Yan Jin Liu Gu", we learned that the calligraphers Yan Zhenqing and Liu Gongquan of the Tang Dynasty were known as Yanjin Niuhu. A calligrapher refers to a person who is good at calligraphy and can push it to the height of art. He can reproduce reality and express emotional ideals through aesthetic creation activities, and realize the mutual objectification of aesthetic subjects and objects in imagination.