I've only done a 10km marathon
I'm a beginner with Seorak - I've only been twice and both times barely made it in within 11 hours
I'm not exactly sure, but
Seorak in the 5-hour range is usually advanced...kkkkkkkkkkk
Maybe only one person comes in in the late 5 hours, and I think everyone else is in the 6-hour range..
