Stamps are used as stationery printed on documents to indicate identity or signature. Generally, seals should be dyed with pigments before printing. Those that are not stained with pigment and will appear concave and convex after being printed on a flat surface are called steel seals, and some are printed on wax or wax, or wax prints on envelopes. Made of metal, wood, stone, jade, etc.

During the Warring States Period, Su Qin, which advocated unity, wore the seals of the six countries. The cultural relics unearthed in recent years have pushed the history of seals forward for hundreds of years. In other words, seals existed in the Zhou Dynasty.

Most of the ancient seals handed down from ancient times came from ancient city ruins, rivers and ancient tombs. Some were abandoned by the defeated in the war in exile, while others were abandoned by the dead in the battlefield. At that time, the practice was that the engine was handed over to the seal seized on the battlefield, and officials had to take off the seal after transferring their posts and dying. Many others, such as official posts with names, auspicious seals, Xiao seals, etc. Generally, they are sacrificial offerings, not physical objects.

Other pottery and standard measuring tools of the Warring States period, as well as gold coins of some vassal States, were all stamped with seals, and the names of craftsmen or symbols with icons were recorded, which were also handed down.