10 Pfennig A. Diehl Baugeschäft

A. Diehl Baugeschäft was a construction firm in Essen-Ruhr that, like hundreds of German businesses, resorted to issuing its own small-denomination cardboard emergency money during the acute coin shortage that followed the First World War. This is Notgeld in its most stripped-down commercial form — a private employer paying out small change to workers when the Reichsbank simply could not supply enough physical coin to meet daily wage transactions.

The serial number is the only concession to security, which tells you something about the trust model: these circulated within a known local community, not anonymously.