20l blue canc. "ΚΕΡΚΥΡΑ*2?.ΟΚΤ.7?", triple control numbers, second control number in a distance of 2mm vertically printed lighter, while there are traces of a third control number, a third digit "0" is visible. A case not mentioned in Koundouros study under 63.6 error. Bottom margin touches frame line, while right margin cuts frame line, still fine for this impressive control number error. (Hellas 51bNoII).