Two Chinese characters Ban Liang ("Half an ounce"), outer rim / Flat, no rims. 22mm, 2.86 grams. Gratzer/Fishman "The Early Round Coins of China" #13.51; Hartill #-.

Unusually small example.

The Ban Liang coinage consisted of round bronze coins with a square central hole first introduced by the Qin State in the 4th century BC and standardized after the unification of China by Qin Shi Huang in 221 BC. Inscribed with the characters Ban Liang ("half liang"), these coins were supposed to weigh half of a Chinese ounce (liang) of about 16 grams. The earliest "Ban Liangs" weighed half that much - 8 grams (and sometimes more), but the later pieces, like this one, weighed much less. These coins replaced the diverse regional currencies of the Warring States and became the first standardized coinage used throughout a unified China. Ban Liang coins remained in circulation until they were gradually replaced by the Wu Zhu coinage under the Han dynasty in 118 BC.

This coin is unconditionally guaranteed to be authentic