Yan Ti Kai. The regular script with a narrow Yan style that is thick at both ends and in the middle is beautiful. Yan style is a font created by Yan Zhenqing, a calligrapher in the Tang Dynasty. Together with Liu Gongquan, it is called "Yan Liu", and there is a saying of "Yan Jin Liu Gu". "Yan style" refers to Yan Zhenqing's regular script, which has a square and dense structure, light horizontal strokes and heavy vertical strokes, powerful and round thick strokes, and a solemn and vigorous momentum.