25 kg Eisen

The Deutsches Reich issued a series of commodity-backed certificates during World War I as the traditional money supply buckled under war finance pressure. The 25 kg Eisen — iron, not gold or silver — reflects how far the Reich had stretched the concept of backing currency with tangible value. By anchoring denominations to industrial raw materials, the government attempted to stabilize confidence at a moment when metal coinage had largely vanished from circulation.

The tiny physical dimensions put this firmly in the Kleingeldersatz category — emergency fractional currency, not a banking instrument.