1916 incoming cover endorsed ‘O.A.S’ from a Cook Islands native to Rarotonga, and cancelled FIELD POST OFFICE D. Z. 18 JY 16. A Cook Islands 2 SP 16 arrival cancel is on the back. He was part of the small contingent of Cook Islanders who fought in WW I. They were attached to the New Zealand Division and up until September 1916 were on the Western Front. The cover has been censored with a red 3643 censor cachet and a pencil ‘censored J H. Hall’ is handwritten. An exceptionally rare cover from a Cook Islander fighting on the Western Front.