cover 1941 (7 Dec) envelope from Tung Pi to U.S.A. endorsed "By Air Mail to Hong Kong" and bears a boxed cachet in Chinese stating "Due to War in Hong Kong, Postal Route is blocked, Return to Sender" (subsequently crossed through). The letter eventually went via Burma and India with censor label and h.s.; reverse bears boxed strike in violet in Chinese "Airplane not flying, delay for several days"; minor wrinkling