Hong Kong. (Prisoner Of War Mail). 1917. Stamp-less envelope headed 'Prisoner of War' and endorsed 'F. Wirth, Prisoner of War No 370 at Hong Kong' with m/s date '17/15/17' in blue crayon addressed to Austria with framed 'Passed By/ Censor/ Hong Kong (Crown)' on face and boxed 'Zensur/ Wien' applied on arrival in red. Very fine.