What calligraphy is a three-character pen?

Three strokes generally refer to pronouns written in three ways, namely, pen, chalk and writing brush. Although the line expressive force and artistic appeal of pen characters are not as rich as brush calligraphy, they are far better than other hard pens such as pencils and ballpoint pens, because the nib is elastic and the strokes written are also clear and thick. Brush writing refers to words written according to traditional statutes, rather than words written casually with a brush. Calligraphy is a line plastic art, and chalk characters refer to characters written with chalk made of calcium carbonate, calcium sulfate and a small amount of calcium oxide.