U.S. Postal Agency, Shanghai, China, Oct 5, 1918, clear strike of duplex cancel on cover with "Knights of Columbus War Activities" part-printed return address to Los Angeles Cal., purple "A.E.F. Siberia, Censored" boxed handstamp, signed by censor, some edge flaws and surface abrasion, F.-V.F., a scarce use. Estimate  $200 - 300. The first American troops of the A.E.F. arrived in Siberia in Sep. 1918 and authorization for establishment of a postal agency followed soon after, no special datestamp was immediately available and so this U.S. Postal Agency in Shanghai marking was used on a provisional basis until the correct handstamp could be supplied. This temporary use of the Shanghai marking was only operational for three weeks until Oct. 17. $0 (Image)