Ming Knife

Yan was the northernmost of the Warring States, perpetually pressed by nomadic incursions along its steppe frontier and chronically short of the resources that fueled the richer southern kingdoms. Its knife money persisted long after most rival states had transitioned to cast spade or round coinage — a conservative monetary choice that likely reflects Yan's geographic isolation as much as any official policy. The state finally fell to Qin in 222 BC, just two years before unification extinguished every regional currency at once.