You’re in charge of the mail for a newly-independent country following a brutal war and an extended time of chaos. You need to create stamps as soon as possible, but most of the paper was used in the war. What do you do?
This was exactly the problem that Latvia faced after World War I and the Russian Revolution. Originally under Russian control, and then occupied by German forces, Latvia had few resources left. In 1918, one week after the end of World War I, the country declared independence.
There was a lot of work to be done to secure stability for the new country, and creating a good postage system was among the top priorities. Before the war, Latvia had been part of the Russian Empire, and used Russian stamps. During the war, when German forces occupied it, the country had used German stamps. Now, they needed their own postage. But stamps need paper, and there was an extreme paper shortage from the war. The Latvian government soon realized that there was one good source for durable stamp paper: the military maps of the occupying German Army.
The map stamps came in sheets of 228 stamps, in 12 rows of 19. On the back of the existing stamps, sections of Latvia are still evident, with names and grid positions. The new Latvian government only printed 11,956 sheets; fewer than 5000 were perforated. Only 4750 actually made their way to the new government by 1919.
The Republic of Latvia was short-lived; in 1939, the Molotov-Ribbentrop Pact awarded the country to the USSR. During World War II, both the USSR and German armies occupied the country at different times. Finally, in 1945, it became the Latvian Soviet Socialist Republic. After many years as part of the USSR, the Republic of Latvia once again declared independence on August 21, 1991, after a failed Soviet coup attempt. It joined NATO and the European Union in 2004.
There are many photos of Latvia map stamps here. Some excellent in-depth information on the stamps can be found here.