Sweden. Facit 33v1 ★, 20 öre red with 'TRETIO' instead of 'TJUGO' variety (a few short perfs). Unusually well centered unused example of this World famous error, with interesting background of the origin in enclosed article. Certificates The Philatelic Foundation (1962) and M. Nilsson 2, 4, 3 (2024). Ex. Contenta. SEK 100000
