Ten centimeters. According to the Weizhi Shujian website, we learned that when writing facial expressions while sitting, using a ten-centimeter pen can reflect the fullness and plumpness of the fonts and clear lines. The stipples on the structure appear compact, and the layout of the strokes is more symmetrical, making the lines rich and smooth. , so it is better to write facial expressions while sitting down with a pen of ten centimeters. Yan style is a font created by Yan Zhenqing, a calligrapher in the Tang Dynasty.