Bidspirit auction | One Man Collection of Tannu

One Man Collection of Tannu Tuva - 15th Anniversary of Independence - 1937 (March 13), registered cover to Switzerland, franked by 3k and 20k from the issue and air post stamp of 3a, tied by violet Kyzyl letter ''c'' date stamp (Ustinovsky No.3.3.), Berne ''1.IV.37'' arrival postmark on reverse, VF and scarce franking, Est. $400-$500, Scott #73, 81, C18