The ancients said: "Make the pen heart always move in stippling", that is, the center refers to the pen. The center pen can't be too dry, and it can't be finished at once. You should lick the pen at any time as needed and keep it "conical".
In addition, the effect of center stroke is also related to writing speed and familiarity with writing skills. Therefore, for the center, there are two kinds of calligraphy effects: one is "folding hairpin"; Second: "Leak marks". The lines of the two special effects give people a sense of beauty, but the charm is completely different, one is "charming" and the other is "vigorous".
The former writes fast and the latter writes slowly. Of course, deliberately fast or slow in writing can't achieve the goal. This is also related to the skill of calligraphers. In the process of writing, gently turn the pen so that it becomes the center from the side. Teacher Chen Zhongjian has a video of changing the style of writing, which I have seen.
I was lucky enough to see a video yesterday, which said "Dover Tower". The teacher of the demonstration should use the method of turning the pen. We should learn to use tone adjustment in writing.
Some people scratch the edge of the inkstone when they write a word (even some people adjust the strokes when they write two strokes), which is a bad habit, and you need to pay attention to learning calligraphy. Of course, learning this skill takes a long time to think and explore, and it can't be achieved in one day.