1935 (July 4) London to Shanghai "Return to Sender" and “P.T.O.” Cover Sent from South Kensington to Lt. Commdr. A. Yates at the
1935 (July 4) London to Shanghai "Return to Sender" and “P.T.O.” Cover Sent from South Kensington to Lt. Commdr. A. Yates at the Shanghai Club, redirected to the Admiralty, London. Features a GB 1½d Silver Jubilee stamp and a reverse block of 4x 1c Chinese postage due stamps tied by Shanghai cancels. The delivery failure is meticulously documented by three boxed instructional marks: "1ST NOTICE SENT" (Aug 7), "2ND" (Aug 12), and "3RD" (Aug 21). Includes a bilingual "Returned to Sender" wavy line handstamp and a London (Sept 13) arrival mark. A manuscript mark of "P.T.O." (Please Turn Over) was made on the front – this is alerted by postal clerks to direct attention to the extensive markings, Chinese stamps, and redirection instructions on the reverse of the envelope. This cover illustrates the disciplined three-stage notification attempt used by the Chinese Post Office before returning the item to the UK. The combination of British Jubilee commemoratives and Chinese definitive stamps makes it an exceptional piece of inter-postal and military history plus manuscript instructional marking.1935年倫敦寄上海「退回發信人」封，貼 英國銀禧紀念郵票 寄上海總會海軍少校。背面貼 四連支1分帆船票，並完整蓋有 8月7日、12日及21日之三次催領通知戳記。本封詳盡記錄了中國郵政對海軍郵件的死信處理程序，是研究中英軍事郵政史之經典實物。
