Why should the movement of the wrist be emphasized in calligraphy?

Calligraphy pays attention to spirit, brushwork, facial charm and wrist strength. It can be said that the hidden front of a calligraphy work is restored by experience, which is very skillful. Every stroke is the essence of wrist movement. Yan Zhenqing's calligraphy, the swallow-tailed silkworm head, relies on the unique method of wrist movement. Have you seen Zhang Xu's Weeds? This is the result of wrist movement and instant agility. Wrist movement is an essential skill in calligraphy creation.