Commonly mistaken as a ripoff of kendo, kumdo is a korean martial art that was developed in conjunction with kendo, its Japanese counterpart. Contrary to popular belief, it was Korea who introduced swordsmanship and swordmaking to Japan, hence the "katanas" you see in koeran dramas.
Many Japanese claim that Koreans are using Japanese swords in dramas, as they do not realize that "katanas" are not uniquely Japanese.
Korean "katanas" are more diverse, and called hwando, yedo, or jingum
Kumdo means "way of the sword."