Zhai Zhang Hao Shi Chuanzhai Zhang Hao began with the imperial seal of Li Miduan's bedroom in the Tang Dynasty. After the Song and Yuan Dynasties, this trend became more and more popular, and almost everyone in calligraphers had the seal of fasting.
The seal on calligraphy works is an indispensable part of calligraphy works. Without a seal, it is not a complete calligraphy work. Signing and stamping calligraphy works to show solemnity can prevent forgery.