Again, they had the martial arts, but it was military based not style or systematic based like Karate we see. Depending on which dynasty we are talking about, most people were born into their roles. So if you were born into a military family, chances are you would be learning martial arts and becoming a soldier/officer. If you were born into a scholastic family chances are you would be a teacher or government official. So martial arts were always there. It was through strategic martial arts that Korea was able to fend off many invaders such as the Hun, Chinese and even earlier Japanese invasions. They even, at one point, stopped US Admiral Perry from docking. It was then that Perry went over to Japan and forced his way there.Given that the martial arts had not been a huge part of Korean culture for probably a couple of centuries, probably more, prior to the occupation, I think that you're asking the wrong question.