The Ban Liang (Traditional Chinese: 半兩 ; Pinyin: bàn liǎng) was the first unified currency of the Chinese empire, first minted as early as 378 BCE and introduced by the first emperor Qin Shi Huang as China's first unified currency around 210 BC[1] (although coins with this inscription already circulated in the State of Qin prior to unification). It was round with a square hole in the middle. Before that date, a variety of coins were used in China, usually in the form of blades (knife money, spade money) or other implements, though round coins with square holes were used by the State of Zhou before it was extinguished by Qin in 249 BCE.[2]
The Ban Liang corresponds to a "half tael" (半兩), or twelve zhu (銖, about 0.68 grams). It typically weighs between ten and six grams, roughly corresponding to the Greek stater.
The standardization of currency with this round coinage was part of a broader plan to unify weights and measures during the Qin empire.[3][4] Ban Liang coins continued to be used under the Western Han dynasty until they were finally replaced by the Wu Zhu cash coins in 118 BC.