It is believed that seals came out as early as 8,000 years ago after our ancestors could make pottery wares and had private property. They were assumed to make marks on their own possessions to prevent theft. When the first dynasty was established, the king began to use seals to empower and to show lordly credits. Only the king's special seal was then called 'Xi', which represented the highest authority. The first emperor of China, Qin Shi Huang, had his 'Xi' made out of the invaluable and beautiful jade 'Heshi Bi'.
Then followed the local governments who needed seals for similar function. Simultaneously private seals were carved in a variety of auspicious characters and vivid animal patterns. Gradually the sphragistics came into being. Now many collectors' favorites are of that kind.
The heyday of seal history was during the Ming (1368-1644) and Qing (1644-1911) Dynasties when the feudal arts flourished. As wash paintings thrived, artists stamped their seal on the 'xuan,' a special kind of high quality paper used for painted scrolls in order to identify themselves and to add interest. Various sects of carving were erected by noted seal cutting sculptors.
A craftsman is making a seal
Another noted seal engraver was He Zhen of the late Ming Dynasty. He used the graver steadily and neatly with strength and vigor, and the curves of each character were quite clear and harmonious. His works stopped the vogue of affectation and influenced the engravers of the Qing Dynasty.
The genre of seal is greatly determined by the strength and speed of wrist and hand. Seals, like a person's character, are distinctive from each other. A sanguine seal engraver makes deft and buoyant strokes while a sober person makes careful and neat ones.
Seal carving also requires choice materials like metal, jade, animal teeth and horns, pottery, bamboo, fruit-pits, and stones. A good material should feel slippery, smooth, cool at first but warm after a second; when cut, it should have certain flexibility. Qingtian stone, Tianhuang stone, Balin stone and 'chicken's blood stone' (Jixue shi) are all first-class materials among stones used for seal cutting. Tianhuang stone features its translucency; 'chicken's blood stone, the red dapples.