Ningen tte Sonna Mono Ne from her album "trip trip," I really like the piano rearrangement on this version. It's also interesting to note how her voice has changed throughout the years. Regardless, she sounds amazing.
My other favorite KOKIA Lives here:
http://www.youtube.com/playlist?list=PLukIoKUw4ng8cVKeEj-KqSRIlGl3_PiE0
Home » プレイリスト » Youtube » KOKIA - 2012 concert tour「History」 - 人間ってそんなものね