1870 50c Ocher and carmine, inverted numeral, the phenomenally rare error of the early postage due printing, attractive colors in the early printing shade of the ocher frame, o.g., h.r., trivial gum tone speck of no consequence, usual fine centering that this rarity always possesses and exceptional in this mint original gum quality.The rarity of this inverted numeral error is often not recognized because the later 1890 50c Orange and carmine is relatively common with inverted numeral in mint condition. However the colors are distinctly different, just as the brown and carmine numerals are different on the high values between the two printings and the two printings are easily differentiated. Scott does not do collectors a favor by failing to list them, even though they make note of the two different issues in a footnote.The used 50c value with inverted numeral of this printing is quite rare (see the next two lots) but available. In mint quality, however, this value is one of four that Sassone acknowledges as existing in mint or unused condition but does not price. The other three are the 30c and 60c of which only one unused and one mint example respectively are known, plus the 10L of which there are three examples known, all without gum. No quantity is given for the 50c value, but it is as elusive as these other values and a great postage due rarity of Italy and of the entire world. This example has long been known and is signed by E(milio) D(iena) and E(nzo) Diena (Scott #J10a var.).