Speaking of which, this center issue is quite mysterious. As the predecessors said, a darker black line can be seen in the middle of the written strokes, which means that the middle of the strokes is darker. , the colors on both sides are lighter and have a three-dimensional effect. In fact, if you look at the works of ancient, modern and modern famous artists, whose strokes can have this effect? No. The works written by Dong Qichang have obvious three-dimensional effects, but he used a special method. However, whether it is a center or not, from another perspective, it means that the edges of the written strokes must not have jagged or ink-colored edge effects. This effect can only be clearly seen on rice paper. As long as it appears, it means that it is an obvious forward. If it does not appear, even if it is not a center, it is not far from the center. This situation is easier to detect when you are writing, because when you move the pen, the brush hairs are very flat and evenly distributed, which is the center; if the brush hairs are biased to one side, it is undoubtedly a slant. When learning calligraphy, it is indeed very important to master the center. This is a basic skill. If you do not master it well, the strokes you write will float, and the beauty will be poor. But it is impossible to be a center forward. How to master it? Don't be hasty, just use your wrists to straighten the brush hairs as much as possible during practice. As time goes by, you will form a habit and you will master this skill. I wish you progress!