A very attractive trojak, which is not only rare in terms of variety, but is also illustrated in Tadeusz Iger's catalog.
The coin is a variety with a mint mark at the end of the obverse legend (referred to as R3), but additionally with an unprecedented error in the reverse legend - PO-OLONIAE (instead of POLONIAE).
This error was so rare that T. Iger did not have it in his collection, and in his catalog he illustrated it with another collector's coin, this one (which can also be seen from the different style of the photo).
A trace of a patched hole, otherwise a very good presentation.