Short, middle and long; single or double; straight or inverted. The most popular weapon. Korean swords varied greatly in size, shape, and style. The governing philosophy was that every sword should be custom made to suit the size and strength of it's wielder.
Korean Swordsmanship Black Belt Magazine, March 1999. Jane Hollander interviews Barry Harmon in a discussion of Korean swords and sword techniques.
Korean Swordsmanship article in the English Wikipedia.
There are a truly staggering variety of ancient Korean swords. Here is a collection of different types: