Here's what i've just found.
Anyone interested in??

http://www.jarasumjazz.com/

There are some pretty good artist that are going thanks for sharing that.

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Just my humble opinion!

I went to this a few years ago and really enjoyed most of it. They get world-class jazz bands/musicians to perform, the parking is plentiful (although pretty long walk from the parking lot), and the food tents have everything you could ever want (a little pricey by Korea standards though). There are some nice arts and crafts type presentations also.

The thing that annoyed my the most were the kids and people who came to socialize and not watch the concerts. A lot of people made it a family event. Of course, nothing wrong with that. Except they brought a gaggle of kids who had no interest whatsoever in the concerts, so they tore around the crowd playing grabass the whole time, and it was really annoying. And there were groups of people who did nothing but talk the whole time during the shows.

All in all, it's well worth the trip if you like jazz.