This 1937 issue from the French Post Office in Kouang-Tchéou (Kwangchowan) features a black overprint reading "KOUANG-TCHÉOU" on a 6 centimes red stamp originally issued for French Indochina. The design depicts the ruins of Angkor, symbolic of the cultural richness of France’s Southeast Asian colonies. Printed in Paris by Hélio-Vaugirard using photogravure, the stamp was designed by Antonin Jean Delzers and Gabriel-Antoine Barlangue. It measures 24 x 20 mm and has a perforation of 13½ x 13. Issued for use in the leased Chinese enclave of Kouang-Tchéou, this was part of a broader colonial postal strategy reflecting regional administration within French Indochina. The presented block of four is mint never hinged, from the lower left corner of the sheet, showing full original gum and pristine selvage. Cataloged as Scott KT113, Michel FR-IC B143, Yvert FR-KT 107, and Stanley Gibbons FR-KT 108. In outstanding condition and highly collectible due to its corner margin and postal-historical relevance. Estimate "$80 – 100"