:Within the WP:WPMA it has been the convention to treat names of martial arts as common nouns (not capitalized), and not as proper nouns.  Where the word "taekwondo" is part of a proper name, such as an organization, it should be capitalized along with the rest of the name, such as Rhee Taekwon-Do (where it is also written according to the "official" name of the organization).  So the first line of that article might read: "Rhee Taekwon-Do is a school of taekwondo."