Today, calligraphy pays attention to change. When the same word appears in a pair of words, you can use the front to adjust the change. Generally speaking, the structure remains unchanged. Of course, there are also cases where the structure has changed. Anyway. According to your own mood. Running script has many fronts, because it is inevitable to show them when written quickly.
From the point of view of calligraphy, using a pen is expensive. Use front or right, side, reverse, smooth, reusable, lightweight, practical, empty ... all depends on the sharpness of the pen tip. If you use the center, the pen will be heavy; If you use the Tibetan front, use the pen to make the stippling "hide the tendons and hold the bones"; If you use the reverse front, you can make the stippling strong and thick; If you use the exposed front, you should use it vertically; If you use the flank, you have to take risks with the flank. From the positive point of view, these all have their own advantages and are opposite to each other. Novices should pay attention to the front of the pen to achieve the effect of "penetrating the back of the paper". If the front is flat, stippling will become dull.