Hong Kong. (British Post Office In China). 1918. Registered envelope addressed to Canada bearing British Post Office in China SG 3, 4c carmine (pair) and SG 7, 12c purple/ yellow tied by Canton/ B date stamp (Webb Type Eii) with framed 'R/ Canton B.P.O.' on face routed via Hong Kong with Vancouver and Winnipeg arrivals on reverse. Scarce registered cover from British Post Office in Canton.