Guang Han Da Jiang Jun Zhang (Seal of the Great General of Guanghan), Western Han Dynasty (202 BCE—8 CE). Silver. Length 2.35 cm, Width 2.35 cm, Height 2 cm. © Shanghai Museum

The Qin and Han official seals were established with strict hierarchy marks. Different seal knobs and seal materials represented different social ranks, varying from the Son of Heaven to subordinate officials. This silver seal with turtle-shaped knob was the official seal awarded to 'the Great General of Guanghan' in the late Western Han dynasty. The shape and structure of the turtle-shaped knob imply the art of being a minister - to retire after success.