Regular script is a font that is slightly modified from official script. It was formed around the end of the Eastern Han Dynasty and gradually matured during the Wei and Jin Dynasties. It preserves the structure of the official script, removes the corrugation of the official script, and changes the flat shape of the official script into a basically square shape. Later, people often called Chinese characters "square characters", which was for regular script. Regarding the emergence and development of regular script, Kang Youwei said in "Guangyizhou Shuangji": "Did the change of true script occur between the Wei and Han Dynasties? There was no true script style before the Han Dynasty. The true script has been passed down to today since Wu Zhi's " "Ge Fu Jun Stele" and Yuan Chang (Zhong Yao)'s "Li Ming", "Rong Ge", "Xuan Shi", and "Jian Jizhi" all began to change. , not Xiaoyi. "The real script he is talking about is regular script. Since the Six Dynasties, this new font has been called Zhenshu or Zhengshu. In the Tang Dynasty, this type of script developed greatly, probably because it served as a model for people to learn and imitate, and it was called regular script. The characteristics of regular script are horizontal and vertical calligraphy and painting, compact structure, smooth momentum and graceful shape. Calligraphers in history have many fine works handed down from generation to generation. Ouyang Xun, Liu Gongquan, Yan Zhenqing, and Zhao Meng developed regular script to its peak with their unique styles, and are known as the four masters of regular script. Because regular script is easier to write than official script and easier to read than cursive script, it gradually replaced official script after the Wei and Jin Dynasties and became a universal font, which has been used until now. In the Song Dynasty, due to the development of printing technology, a type of font specially used for printing was gradually formed based on regular script, which was later called Song style. Nowadays, Song fonts, imitation Song fonts, Hei fonts, etc. used in computer typesetting and various printed materials are all variations of regular script.