3 Ngr. King Johann I, two folded letters each with single franking, chiefly notable for Prussian framed railway post mark POST SP. BÜR. IV. GOERLITZ-KOHLFURT on reverse, one in black, one in red. Grobe handbook values red at c. 600,-- Ç; black reportedly even rarer and difficult to value. Both letters in fine condition (previous starting price 150)