Ban Liang
The Ban  Liang (Traditional Chinese:  ; Pinyin: bàn liǎng) was the first unified currency of the Chinese empire. It was first minted as early as 378 BCE. The coin was introduced by the first emperor Qin Shi Huang around 210 BC. It was round with a square hole in the middle. Before that time, many different coins were used in China. They were usually in the form of blades (knife money, spade money) . Round coins with square holes were used by the State of Zhou before it was ended by the Qin in 249 BCE.