This is somewhat old news, but I just found out, so...
It was announced on the official site of Mika Nakashima, that the 27 year old singer will temporarily stop all activities as a singer to focus on correcting a deterioration of her ears. The singer is currently suffering from an opening in the eustachian tube, a condition that has already made it very difficult for her to continue singing.
She might be best known for singing Yuki no Hana which has been translated to Korean, Chinese (Mandarin and Cantonese), and even English. Its words are so touching that East Asians stop hating each other for a few minutes.
There are a ton of covers by amateurs and pros alike on YouTube.
I didn't know this before, but at the end of the last video, she said that she didn't go to high school herself. (I knew that in Japan, high school wasn't mandatory, but almost everyone went anyway, but I guess she skipped high school and went straight into entertainment.) I suppose this let her experience a high school graduation in her own way.