The seal is the official seal. As a status symbol, it not only has the function of front printing on official documents, memorials and other documents, but also has the function of local printing on private letters, stationery and other documents. Therefore, the seal has both the authority and credibility of the original print and the privacy of the partial print, which can be said to be both the original print and the partial print. The size, shape and material of seals used by officials at all levels are also different, which reflects their position and political status.
Since ancient times, the official seal has always been an indispensable part of official etiquette. It is a general term for official seal, partial seal and dragon seal, which reflects the different political status of officials with different levels and identities. There are "three seals" in Shangshu, namely, emperor seal, prime minister seal and imperial history seal; In the Ming and Qing Dynasties, there were "seven-grade seals" and "nine-grade seals" to divide grades; In modern times, letters are printed according to different categories, such as official seal, special seal and contract seal. Because of its special significance, the official seal is also reflected in culture, calligraphy and other aspects, and has become a very valuable and attractive part of traditional culture.