50 Pfennig - Erfurt Reibstein

Erfurt's Reibstein notgeld issues belong to the wave of privately-struck emergency coinage that flooded Germany between 1917 and 1921, when wartime metal shortages forced municipalities and private firms alike to produce their own subsidiary coinage. Zinc was the compromise material of the period — iron rusted, copper was strategic, and aluminum was reserved for larger denominations.

The Menzel reference numbers suggest this is a documented variety with at least minor catalogued distinction from related issues in the same series.