½ Liang (Type 4; with Wu below)

The Ban Liang coin, or half-liang, originated during the Qin Dynasty as part of Emperor Qin Shi Huang's efforts to standardize currency across a newly unified China. Moving away from the diverse, regional spade and knife currencies that had dominated the Warring States period, the central government mandated these circular copper coins with a central square hole. This design established a standard that would persist for over two millennia, symbolizing the harmony between the circular heavens and the square earth.

This specific variant, characterized by the inclusion of the 'Wu' character beneath the weight designation, emerged during the early Han Dynasty transition period, specifically around 175 BCE. During this era, the central government grappled with issues of private minting and economic instability, leading to various adjustments in coin weight and inscriptions to curb counterfeiting. The bold, utilitarian calligraphy reflected the transition toward a more structured imperial administration, prioritizing functional durability and clear identification for regional commerce.