Issued on May 23, 1941, this block of six mint never hinged stamps features the Junkers F-13 monoplane flying over the iconic Great Wall of China, a powerful image symbolizing both modernity and national heritage. Part of the Hong Kong-printed airmail series by Commercial Press Ltd., this issue was printed via gravure and bears no watermark, with varying perforation as typical for the printing batch. The vivid "ed" color tone and finely detailed engraving highlight the mountainous landscape and stone ramparts in the background, with traditional Chinese architectural elements rendered beneath the soaring aircraft. These 30-cent stamps were used to cover standard airmail rates during a time of increasing geopolitical tension across East Asia. The block is exceptionally preserved, mint never hinged, with full original gum, sharp edges, and clean perforation alignment across all six stamps. Catalogued as Michel CN-IM 371, Scott CN-IM C34, Yvert et Tellier CN PA24(B), Stanley Gibbons CN-IM 557, and China Stamp Society CN-IM AM41. Estimate "$140 – 180"