CHINA. 1939 air mail cover, with HK Great Wall air mail 15c pair tied by Lanchow Feb. 8 c.d.s. to Shanghai, with arrival c.d.s. on reverse. Official Seal label tied by "Received in Such Condition" chops were put on by Shanghai PO upon receiving, perhaps used as censor Showing embossed Mission red seal ' Vicariatus Lanchowfu-Provincia Kansu Scarce usage. (Photo). Est. 200 - 300 CHF.