OFFICIALLY SEALED LABELS: A specialised collection on leaves with the overprinted issues in unused singles and multiples, "MANCHOUKUO/POST OFFICE" label in red in singles and multiples from the different issues and with varieties including imperf., imperf. between, têche-bêche, paper fold prior to printing, offsets, misplaced perfs. and others; also a few other items. A desirable and scarce study