1 Cash - Yuanfeng Tongbao, Seal script, iron

Yuanfeng was the reign era of Emperor Shenzong of Song, and the cash coinage of this period was issued in both bronze and iron — iron being pushed into heavier circulation as copper shortages bit into Song fiscal policy. The northern frontier wars against the Xi Xia and the ongoing costs of Wang Anshi's reform programs strained metal supplies badly enough that iron cash became a practical necessity rather than a marginal alternative.

Hartill 16.222 places this among the seal-script varieties, distinguished from the running-script issues struck concurrently. Iron Song cash corrodes aggressively, and survivors with legible characters are considerably less common than the bronze equivalents.