[Leftium]

There is also a Category V, which requires twice the study hours of Category IV (2200 hours) [1].

Last I heard, Category V was an unofficial level, and Korean was the only language in the category. It seems they made it official and shifted the languages around (interestingly, German is only language in Category II, now. And Japanese is considered more difficult than Korean.)

[1]: http://www.effectivelanguagelearning.com/language-guide/lang...