What is the meaning of hidden front in calligraphy?

When starting a pen, you usually use a hidden front, which has certain emphasis and expression: you should first go down right (horizontally) and down (vertically), so that the strokes will be round without revealing the nib, and when starting a pen, you should hide the front, but you don't have to hide the front when writing, but you should be careful not to cross, and you should also close the front (back) space; After the hook, the front should also be empty, and the strength is subtle and calm. When you start a long vertical pen, you should hide the front, and when you close it, you should go back to the front. The words hidden in front of them look powerful and have an inherent implicit aesthetic meaning.