1/2 Mark Herzhorn

Herzhorn is a village in Holstein, and its half-Mark notgeld is among the smallest-format emergency issues of the WWI period — a consequence of the chronic small-change shortage that hit rural German municipalities particularly hard from 1916 onward. Local authorities were permitted to issue their own temporary fractional currency when the Reichsbank could not supply sufficient coin, and hundreds of Gemeinden took up that authority.

At 58 × 41 mm, this is genuinely pocket-sized — closer to a postage stamp than a banknote. Paper this small degrades quickly in daily use, which accounts for the difficulty in finding undamaged survivors.