Inverted overprints exist for only two denominations. It is believed that for No. 5, only two sheets were produced with this error (one on offset and one on pelure paper), while for No. 7, only a single sheet was invertedly overprinted. These stamps are scarce, especially No. 5 on pelure paper, which was discovered much later. Inverted overprints are exceptionally rare in multiples, with blocks of six being the largest known units.
1945 Zagreb Provisional Issue, Nos. 5 and 7 With Inverted Overprint. The Largest Known Multiples.
