Why is 1943 Šibenik inverted overprint so rare? When using the printing machine a whole sheet is overprinted at once, hence one mistakenly inverted sheet results in many (usually 100) inverted stamps. On the other hand, printing by the hand allows that each inverted overprint is noticed and corrected immediately, so the next hit is already the correct one.
1943 Šibenik local provisional issue, 1 lire air mail stamp with inverted overprint. Certificate Zrinjšćak, Marinšek. This is one of the two inverted overprints I have ever seen.
