20 Mark

Neckarsulm's 20 Mark notgeld of 1918 was issued under the emergency currency provisions that allowed German municipalities to plug the coin shortage caused by wartime metal requisitioning. Neckarsulm was a modest industrial town in Württemberg — home to the NSU factory, which had shifted to military production — and like hundreds of similarly sized communes, it printed its own fractional and low-denomination paper to keep local commerce moving.

The embossed seal was the issuing authority's primary authentication method, a low-tech solution that nonetheless deterred casual forgery when centralized oversight was impossible.