Uniform production provides a very good economical and military indicator on the country producing them.
This is why many countries have this very sensible information coded. In early years of WWII, Nazi Germany only coded the name of the towns where uniforms were manufactured but did not code the year of manucfacture ; as an example a M 40 stood for München 1940. The name of manufacturers also appeared on most items.
From 1943 on, Nazi leaders clearly understood this could provide the Allies with very useful military information such as where manufacturing sites were located, productions levels, quality and quantities... In the last years of the war, the Germans created a special code known as the RBNr code ; the uniforms were marked, for example, as follows : RBNr 05510020 such a number included information such as manufacturer's name, address, year of manufacturing... It is said that the key to the code was lost in the ruins of the third Reich. As a matter of fact, the code has remained unbroken up to now.
Communist Germany known as the German Democratic Republic (DDR in German : Deutche Demokratische Republik) was created in 1948 ; in the first years of its existence, the new-born country was allowed to have only police forces. Those forces gradually organised in military forces and the Nationale Volksarmee (National People's Army) was officially created in 1956 together with its own brand new uniforms. Likewise most countries, the GDR had its uniforms marked. From 1956 to 1967, the marking was not coded : the date was clearly printed. From 1968 on, the date was coded with a letter.
as an example :
NVA 1856 2/N
NVA : Nationale Volksarmee
1856 : manufacturer's code
2/N : second term of 1989
Fortunately, the code has not vanished with the breakdown of the wall. I do not wish do give it on this site for the simple reason why I do not know whether spreading the code-clue around on the net is a good thing... I have read many times about increasing DDR copies on the market ; I think this code clue could help bad traders in their unhonnest job to make their copies look like the closest possible to authentic issues. Anyway... if you have a close look at your items, you can more or less easily find out the date they were manufactered : eg before coming out of manufactures, a sheet or two of newspaper were rolled up and placed inside the caps to maintain the shape ; if you unroll the sheets and read the date of issue, you can find out the manufacturing year with very little chance to be mistaken because most of time the years of paper and cap correspond. Anyway, If you get stuck for a year or two, just drop me a line and I will be glad to help you out.