1/2 Groschen postal stationery card, rare blue K2 "MARTEN 25 8 73 11-12", carried to Dortmund, Hansmichael Krug BPP photo opinion: "This cancellation, rare in blue, is clearly struck twice. The card to Dortmund is correctly franked at 1/2 Groschen under the tariff effective 1.7.1872. ...faultless very good condition."