Great Britain – Türkiye: 1920 (22 October). On Active Service cover from Corporal H. Butcher of the Army of the Black Sea to Salisbury, England struck by ARMY OST OFFICE Y1 datestamp. APO Y1 was a sub-office operated at Çanakkale for the processing of mail from detachments of the Army of the Black Sea in locations without their own offices. This cancellation recorded between 16 October and 4 November 1920 according to Proud.
