Qin dynasty standardizes currency
After unifying the warring states in 221 BC, Qin Shi Huang abolished the regional coinages (knife money, spade money, shell imitations) and imposed a single coin: round, cast in bronze, with a square hole in the middle. The design was called 'banliang', meaning half-ounce. The square hole let coins be strung in groups of 1,000 for large transactions. That shape, the 'cash coin', remained the template for Chinese currency for more than 2,000 years, outlasting the Qing dynasty itself.
The square hole let coins be strung together for large transactions — a simple technological choice with enormous downstream effects. It also made Chinese coinage visually unmistakable across two thousand years of history.
02 · Coined Metal
Money became portable, durable, and unforgeable (in theory) when sovereigns started stamping their seal onto standardized metal. Lydia minted the first coins in the 7th century BC. Within two hundred years, coinage had spread from the Aegean to India to the Yellow River. Trust moved from the object to the ruler who minted it.
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