Chun An Jun (Lord of Chun'an), Zhao State, Warring States Period (475-221 BCE). Jade. Length 2.3 cm, Width 2.3 cm, Height 1.9 cm. © Shanghai Museum.

Official seals in the Warring States Period had reflected the ranking system by using different materials. In the states of Qi, Zhao, Wei and Han, the emperors and lords began to use jade to make their official seals. This jade seal created in Zhao, Wei and Han states was the official seal granted to the Lord of Chun'an, which indicated that jade seals had become a new symbol of social status.