Seal carving
It refers to cutting a design into the bottom face of the seal (the active surface used for stamping, rather than the sides or top).[1] During the Shang dynasty seals started being used in the government offices, where they represented authority and power.During the Shang and Zhou dynasties the materials for seal making were mainly animal bone, copper (bronze), and pottery.During the Qin dynasty the more regular and formal seal script called xiaozhuan (小篆) was formalized by Chancellor Li Si and prescribed by the Emperor Qinshihuang, thus the written script of Chinese characters was unified for the first time.Such seals, beside indicating the producers' names, time, or place, already have various styles, reflecting the personal characteristics of the manufacturers.