1918, 3¢ purple Offset, type IV, printed on both sides, left margin block of 4 with plate "9009" number, o.g., fairly light hinging, strong bold color, impression on reverse with plate "8995" number, reverse with minor offset on top right stamp and certificate mentions left pair with vertical crease which is only a light gum bend that does not crease the paper, Fine, one of two known examples of this variety, the other being a plate number single; with 2010 W. Weiss certificate. Scott No. 530b  Estimate $1,500 - 2,000. AN EXTRAORDINARY EXAMPLE OF THE 1918 3¢ OFFSET TYPE IV ISSUE PRINTED ON BOTH SIDES WITH IMPRESSIONS FROM TWO DIFFERENT PLATES. The plate number single was featured in an article in the Philatelic Foundation "Opinions III" by George Brett. It is believed that the impression on the reverse (plate 8995) was either a makeready or a rejected print and, due to economy measures at the time, the sheet was later reused (probably also as a makeready) when plate 9009 was used a few days later. $0 (Image)