1870 10L Blue and brown, inverted numeral, an incomparably rare unused example of the inverted numeral error of the Ten Lira 1870 Postage Due issue, especially attractive with gorgeous rich colors on paper that is bright white and fresh, the back is as clean as the front, without gum as all examples of this rarity are, in addition this stamp has attractive fine centering with crisp perforations, a choice example of this rarity.Interestingly the used examples of the 10L high value are the most common of the inverted numerals of the 1870 postage dues. Apparently these were virtually all used as the the unused examples are of the greatest rarity. In addition, this is the only Lira value error of the early postage dues that is known mint or unused.The census of this unused error has been noted through the years. At the time of his 1986 certificate Dr. Enzo Diena noted that there were only two examples recorded. The Sassone Catalog now notes that three examples are known and all of them are without gum. This makes this value, along with three other values of this set, among the rarest of the postage due inverted numerals. All are listed but none of these are priced in Sassone. An astounding inverted center rarity of Italy that only appears on the market at infrequent intervals. This stamp is signed E(nzo) Diena and S. Sorani. In addition it is accompanied by a 1986 certificate of Enzo Diena and a 2000 Silvano Sorani certificate (Scott #J19a; unlisted unused).