20 Kop. vertical pair in the block of four! edge respectively corner margin copies, in the middle imperforated! genuine Cyrillic cancel "PSKOW -k -2 1 42"! in cancelled condition hardly known! by of the left upper stamp with plate flaw I, great rarity of the area, unsigned! photo expertize Walter Zirath BPP (2025) : " the condition is perfect. there are only a few pairs known. ", Michel - ., there practically never offered!