Diplomatic pouch tag
This tag was used on a pouch of Registered Mail that was sent from the American Embassy in Korea (APO 301) to the Secretary of State in Washington, DC in December 1960. Alongside the forwarding and return addresses the tag also provides the pouch with a registration and pouch number. It was not however sent via the diplomatic pouch service, which is reserved for official mail, and was instead processed as mail by the embassy’s affiliated APO using normal postage.
Mail sent from foreign embassies has an interesting history. A long standing agreement between nations to allow official mail to travel by pouch uninspected by the host country was formally codified in 1961. Within this employees attached to the embassy were instructed to use proper overseas postage from the host country for their personal mail, which was then forwarded from the U.S .embassy in Washington, DC to the intended address. In 2003 Diplomatic Post Offices were created to handle the personal mail of embassies.
Dattolico, Michael. “United States Diplomatic Mail: Part 3 – Personal Mail Transported in Diplomatic Pouch”. La Posta: A Journal of American Postal History 39 (2008): 46-51.