20 penny medium violet ultramarine, plate flaw IV \"wide notch right besides lower central tip\" as properly franked single franking on cover from \"KAIS. German. P. A. CONSTANTINOPEL * 5 / 7 / 81 2-3 N. \" to Niederuzwil to Switzerland with arrival stamp from 10. VII. 81, in perfect condition, photo expertize Steuer BPP (2022), Michel for single stamp 800.-, on cover not even listed!