"If you are looking for the name of this currency, it's banliang coin. it means "half a liang" and liang was 8 grams- the name referred to the weight of the coin.
Shi Huangdi (whose name can also be written Qin Shihuangdi) was the First Emperor and he also unified China."
it is true that Shihuangdi said that one type of money or currency would be used throughout China.