20 Mark Carl Zeiss

Issued to mark the centenary of the Carl Zeiss Foundation, this coin commemorates the Jena-based optical manufacturer whose foundation structure — jointly owned by the Foundation itself rather than private shareholders — was a deliberate socialist adaptation of Ernst Abbe's original 1889 cooperative model. By 1988, Zeiss had been split between East and West since 1945, with both halves trading under the same name and locked in decades of legal dispute over trademark rights.

The .625 silver specification was standard for DDR commemoratives of this period, a deliberate reduction from finer alloys used in earlier GDR issues as hard currency reserves tightened.