Tonga 1962 1s "Emancipation" 1s blue and black error, SG125aTonga 1962 (7 Feb) "Emancipation" 1s blue and black, type 59 overprint, ERROR OVERPRINT INVERTED, SG125a. A fine used example of this great rarity with part circular date stamp. In superb condition, other than a trivial surface mark. A key British Commonwealth rarity, being one of 28 examples used on first day covers at Vavau (from a half sheet of 30 issued). The overprinted stamps were issued in celebration of the Centenary of Emancipation.