Yumi Kimura (木村 弓 Kimura Yumi?)
She was virtually unknown before the release of Spirited Away.
She writes music, sings, and plays the lyre, a kind of small harp which is heard in the song.
After she saw Princess Mononoke, she was so moved that she wrote a letter to Miyazaki-San and sent her CD. Miyazaki-San wrote back to her and told her about his new project, Rin the Chimney Painter.
Inspired by Miyazaki-San's story, Kimura wrote a song, for which she asked her friend Wakako Kaku to write lyrics. They liked the song a lot, so they sent a tape to Miyazaki-San, hoping that he would like it too.
Miyazaki-San liked it a lot, but the project Rin the Chimney Painter was rejected in the end, so the song was not meant to be heard publicly.
Eventually, it was decided the song would be used as the theme song.
Miyazaki-San says that it might have been because of this song that he could make Spirited Away.
Note: In 2006, Kimura-san appeared with the Eminence Orchestra in a series of concerts in Australia. In the advertising and other literature for this tour (as well as her own handwritten autographs), her given name was romanised as Youmi, which would be pronounced differently to Yumi. However, from the Kanji representation of her given name, it is likely that the name Yumi is meant. It is unclear which of these pronunciations she prefers to use for her given name.