100 Zlotys Mikolaj Kopernik big, Trial Strike Cu

Poland's 1973 Kopernik commemorative program was unusually elaborate in its trial and pattern production — the National Bank authorized copper, silver, and gold trial strikes across multiple die combinations ahead of the circulating issue, generating a documented family of proofs and essais that now populate specialist collections. The "big" designation distinguishes this from a smaller-diameter trial of the same type, a distinction that matters considerably for attribution given how often the two are conflated in general references.

The Fischer and ParM cross-references confirm this as an officially sanctioned trial rather than a private fantasy piece.