This is a postage due stamp from Portuguese Guinea, issued in the early 20th century. The design features an ornate green frame inscribed “PORTEADO A RECEBER” with the country name “GUINÉ” overprinted in bold black. At the center, the value is shown as ½ Centavo. Such stamps were used to indicate underpaid postage, requiring the recipient to cover the shortfall. These classic colonial issues are notable for their strong typography, distinctive overprints, and historical role in the Portuguese postal system in West Africa. A fine piece for collectors of Portuguese colonies and African philately.