5 Zhu ("Western Han" type; unfiled edge)

The 5 Zhu coin was introduced in 118 BCE during the reign of Emperor Wu of the Western Han dynasty. This currency reform was a strategic move to standardize the monetary system of the empire, replacing the lighter, less reliable Ban Liang coins that had been in circulation since the Qin dynasty. By centralizing the minting process and ensuring a consistent weight of five zhu—a traditional Chinese unit of measurement roughly equivalent to 0.65 grams—the Han government sought to curb illegal private minting and stabilize the volatile economy.

The design of the 5 Zhu coin is characterized by its stark, minimalist aesthetic, featuring a square hole in the center of a circular disc, which facilitated easier transport on strings. The four characters inscribed on the obverse read 'Wu Zhu,' signifying both the coin's weight and its nominal value. This design language became an enduring icon of Chinese numismatics, remaining the standard format for imperial coinage for over seven hundred years. Because these coins were produced in massive quantities for several centuries, unfiled edges are common, reflecting the practical, high-volume casting processes of the era.