I trained with GM Chang back when he was an 18 year old 3rd Dan & I was a white belt....before he & his brothers started their own school. I've trained with many people & had several instructors in my 26 years in TKD. Ki Oh Chang is among my favorite people in TKD. He's a good man & a great instructor!
Thanks for the add, Aviador! Those of us who've come to martial arts a bit late in life need to stick together! When I think of how much better my life would've been if I'd found taekwondo earlier, it makes me want to go down to the basement and train! Have a great day!