The vertical axis of official script. According to the query on the Chinese Literature Network, the commonly used font in Cheng Menxue’s calligraphy works is the vertical axis of official script. Official script was used from the Qin Dynasty through the Western Han Dynasty to the Three Kingdoms, before the creation of regular script became mature and popular. But its shape changes and beautifies from time to time. The official script of the Western Han Dynasty still maintained the legacy of the Qin Dynasty. By the Eastern Han Dynasty, especially at the end of the period, it became more neat and delicate. The structure is flat, and there is a wave (捺 in Chinese characters) inside the strokes, forming the basic form of Han Li.