The [[Song Dynasty]] produced more copper coins than any other dynasty; in the 1070s, China was producing nearly six million coins per year, a process which required 9600 tons of copper each year.<ref>Bonnie Smith, et al. ''Crossroads and Cultures'', vol. B, Bedford St. Martins (2012), 385.</ref> Many of these coins made it to Japan, where Chinese coins remained a standard mode of exchange over domestically minted coins throughout much of the pre-modern period. | The [[Song Dynasty]] produced more copper coins than any other dynasty; in the 1070s, China was producing nearly six million coins per year, a process which required 9600 tons of copper each year.<ref>Bonnie Smith, et al. ''Crossroads and Cultures'', vol. B, Bedford St. Martins (2012), 385.</ref> Many of these coins made it to Japan, where Chinese coins remained a standard mode of exchange over domestically minted coins throughout much of the pre-modern period. |