½ Liang (Type 4; iron)

The Ban Liang (Half Liang) coinage was initiated by Qin Shi Huang following his unification of China in 221 BCE, serving as a standardized currency to replace the disparate local currencies of the warring states. These circular coins with a central square hole—a design inspired by ancient cosmological views of the round heavens and square earth—became the template for Chinese currency for over two millennia. This specific iron variant represents a later period of the Ban Liang system, reflecting the economic pressures and metal shortages that often prompted regional mints to shift from traditional bronze to iron production.

The design is strictly utilitarian, prioritizing durability and ease of stringing through the central hole for transport. Unlike later issues that featured more decorative calligraphy, the early Ban Liang issues were characterized by robust, seal-script characters indicating their weight. The shift to iron for this type is generally associated with fiscal instability or temporary metallurgical constraints, marking a significant evolution in the physical material of Chinese imperial currency.