Postal stationery: German Reich postal stationery postcard 15 penny Germania with blue hand stamp overprint "C. I. H. S. ", unused, very fine, expertized Mikulski and photo expertize Gunnar Gruber BPP "they is a very large Upper Silesia rarity. In perfect quality. ", so far are only three further - likewise unused pieces from of this postcard known, large Upper Silesia rarity!