There are many kinds of soft pens (such as soft pens (with rubber heads), writing brushes and chalk), which belong to soft pens. Compared with hard pens, soft pens mainly refer to the written parts. ) Brush can mainly change rich lines, for example, through the ups and downs of the pen, press the pen and lift the pen, draw different forms of lines, with changes in thickness. The expression of Chinese painting and the art of calligraphy are inseparable from this tool.