1881 Tacna Peru - War of Pacific Occupation Mail (Sc. 23, 25; Mi.16, 18)

Chilean Occupation of Peru: 1881, entire letter from Peru to Italia via Panama, bearing Chile 1877 10 c. blue in combination with 1878 1 c. green, neatly tied by cds "TACNA PRINCIPAL 6 SET 81" with adjacent French maritime "PANAMA-UNION PAQ.F.A. N°1 1 OCT. 81" in red (Salles-Nr. 1415), mail carried aboard the Washington vessel. Reverse arrival "BIELLA 23 10 1881". A fresh and very fine entire, correctly prepaid at the inaugural Chilean UPU 11 centavos rate via Panama (with alternative routes charged 10 centavos). Rare example of early UPU mail.

Comment: Tacna, Peru, fell under Chilean occupation on 26 May 1880. Following Chile´s accession to UPU membership on 1st April 1881, the previous foreign single rate of 10 centavos was increased to 11 centavos for mail up to 15 grams via Panama, reflecting the first standadized UPU rate for Chilean international correspondence.