1954 Pof.D89A, 2Kčs violet, marginal block-of-6, shift vertical perf R, unusual; partly detached in horiz. perf 1954 Pof.D80A, Postage due stmp 5h, marginal block-of-6 with shifted perforation up, for comparison normal block of 6; interesting 1946-1971 [COLLECTIONS] / comp. 15 pcs of philatelically influenced letters, from that 12x Reg letter, franked with. Postage due stamps issues 1946-1971 used as postage, with CDS PRAGUE 025/ and PRAGUE 35/ 30.6.88 (last day of validity); by/on/at Reg letters inserted posting cards, very good condition, interesting