40l. dull grey-mauve on blue, control munber displaced (Kound. 54.6), canc. "ΚΩΝΣΤΑΝΤΙΝΟΥΠΟΛΙΣ (ΤΟΥΡΚΙΑ)*21.ΑΠΡ.73" (PO not mentioned in Koundouros study). Stamp with good/even margins but a closing corner. Thinned but still very fine for this very rare and impressive error. (Hellas 42IIb).