10 Zlotys Mikolaj Kopernik, large type, Trial Strike

Poland's postwar monetary reforms left the zloty series in flux through the late 1950s, with the NBP experimenting extensively with module and alloy before committing to circulating types. This trial belongs to that process — the large-module format was ultimately rejected for the Kopernik 10-złotych, with the production coin issued at a reduced diameter. Trial strikes of the larger type reached only a handful of collector and archival examples, making survivors genuinely rare rather than artificially so.

The Fischer and ParM references both classify this as a proof-category essai, struck at the Warsaw Mint on purpose-prepared blanks distinct from any circulation run.