Issued on 9 August 1945 under Japanese occupation of Central China, this mint never hinged set of four airmail stamps features dramatic anti-air raid overprints in the form of stylized bomb silhouettes and text emphasizing defense and regional allocation. The base stamps show aircraft over the Great Wall in various colors—green, orange, blue, and yellow green—each surcharged with new values in Chinese dollars: 150, 250, 600, and 1000 respectively. Printed by gravure without watermark, these stamps measure standard airmail dimensions and were part of a late wartime propaganda and fiscal effort. Listed as Scott 9N111–9N114, Michel JP-CC 104–107, Yvert PA8–11, SG JP-CC 128–131, and CSS SN148–151, the issue blends themes of defense, geography, and aviation. The stamps are well-preserved, with vivid original colors, crisp overprints, and full pristine gum. Estimate $120 – 150