1 Pfennig Köpenick

Köpenick — then still spelled Cöpenick — issued its own small-denomination emergency paper during the notgeld wave that swept German municipalities after World War I, when coin disappeared from circulation and central authorities could not keep pace with local need. The Stadthauptkasse, the municipal treasury, was the issuing body, which was common practice; towns issued through whatever administrative arm had the authority and the rubber stamp.

The B28.3a suffix in the DeNG reference indicates a sub-variety, suggesting the series ran to multiple printings or paper variants — worth checking against the primary catalog before attributing.