50 K. Postal stamp black on dark blue gray, type I, cut, right upper corner of the sheet with overprint \"proof\", as produced without gum in perfect condition, extreme rare stamp from reference sheet springing - issued only 15 examples. Rarity of the German occupation issues in the II. World war. Photo expertize Mikulski and photo expertize Walter Zirath BPP (8 / 2018) : \"the condition is perfect. \", Michel - .