HINDENBURG, Upper Silesia postal stationery card 15 Pfg dark violet Numeral issue 1920 with added Insurgent issue, so-called Korfanty issue, 10 F red, 20 F dark bluish violet imperforate, as collector's cover addressed to Kochlowitz, double-circle HINDENBURG 20 6 21 * (OBERSCHL) 1 p (OS handbook No. 119.18), rare cancel, perfect condition