 Before that date, a variety of coins were used in China, usually in the form of blades (knife 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.The Ban Liang corresponds to a "half tael" (半兩), or twelve zhu (, about 0.68 grams).It typically weighs between ten and six grams, roughly corresponding to the Greek stater.