Liu Gongquan, a calligrapher in the Tang Dynasty, encouraged Jiujing to have exquisite structure.

Yan Gu: It means that both kinds of calligraphy are very powerful, but their styles are different. Liu Shu's brush strokes are clear and bony.

Compared with the two, the remarkable characteristics are: Yan Shu has more muscles, but not boneless, and Yan Zhenqing's book also emphasizes the strength of bones; Liu Shu's bones are bare, but they are not fleshless, but tend to be thin, while Liu Gongquan pays special attention to the bone method.