Bronze banliang coin
From Qin state, China, 3rd century BC
The appearance of round coins in China
The Chinese inscription on this coin reads banliang,
with ban to the right of the hole and liang to
the left. Banliang means 'half-ounce' - the weight of the
coin.
Banliang coins circulated as money in the powerful
state of Qin during the violent Warring States period (475-221 BC).
In 221 BC the Qin state emerged victorious and founded the new Qin
Empire. Qin Shi Huangdi, the first emperor of unified China, also
unified the currency, announcing that banliang coins would
be standard throughout the Qin Empire.
Some people argue that the form of the banliang coin is
symbolic. People in ancient China believed that the earth was
square and heaven was round. So, in issuing these coins, Qin Shi
Huangdi was placing himself as a direct link between heaven and
earth. Others argue that the shape of the banliang is
strictly functional in terms of production technique.
Banliang coins were cast in moulds, and needed to be filed
down after casting. With their square hole, a whole stack of these
coins could be slid onto a square-shaped rod, and all filed down at
the same time.
J. Williams (ed.), Money: a history (London, The British Museum Press, 1997)