The center pen can be used even in calligraphy and painting, but it is necessary to explain clearly the off-center part and the use state at that time. When the center uses a pen, he must have certain skills when carrying it. Liu Xuzai, a calligrapher in the Qing Dynasty, put forward the viewpoint of "going backwards, not moving smoothly and closing tightly", which highly summarized all the skills of writing with a pen. That is to say, the middle stroke stage is not smooth when entering the pen, and the back stroke is used when closing the pen at the end of the stroke.