Although there is a significant number of people interested in uniforms and military insignia, when it comes to the DPRK, there is yet to be a comprehensive study of the subject.

The problem was that every single bit of information related to it is classified. 

It wasn’t always like this. From 1952 until the late 1950s, North Korea did publish some uniform-related material, but this practice was soon ended. Still, North Koreans who served in the military are familiar with rank and insignia structure and one can ask them for information.

Another source would be North Korean films: if a