In 1912, Kamerun established a new system for transporting urgent mail between the various government and military stations without a local post office.  Mail was transported from village to village via couriers traveling on foot.  To denote the special status of this mail, the courier was provided a small black, white, and red flag that was to be passed with the mail from one courier to the next.  The couriers would travel day and night, often covering more than 400 km (250 miles) in 24 hours. 

This service was used for official mail, mail of the various expeditions, and eventually wartime feldpost.  Mail carried via the service typically contains a “Flaggenpost” notation or an illustration of the flag.