It's *태평가/taepyeongga* . Note that it features the melody of *창부타령/changbutaryeong* , a song of the Seoul/Gyeonggi-do folk tradition...this is why the two musical compositions are sometimes mentioned together, or used synonymously to describe what is essentially the same piece.
I find it really amazing that her smile didn't crack, well move, it stayed the same. I'm truly amazed by that. It's a weird comment, I'm sorry but I did love the dance.
