½ Liang ("Elm seed" type)

The Ban Liang, or 'half-ounce' coin, was introduced following the Qin dynasty's unification of China in 221 BCE. Designed to replace the disparate and cumbersome currency systems of the Warring States period, it established the circular shape with a square hole that would define Chinese numismatics for two millennia. The standardization served as a crucial instrument of imperial control, ensuring the Qin government could effectively manage taxation and trade across a newly consolidated empire.

The specific 'elm seed' variation, or Yu Jia Ban Liang, is characterized by its exceptionally small size and light weight, suggesting it was likely produced during the tumultuous transition between the Qin and Western Han dynasties. Scholars generally attribute the emergence of such small, thin denominations to an era of economic instability, where metal shortages or government degradation of currency led to smaller, less standardized issues. While the elegant, minimalist aesthetic reflects the calligraphic styles of the period, these coins remain primary archaeological evidence of the logistical challenges faced by early imperial administrations.