Kubota Keiko（窪田啓子）is a Japanese singer best known for her work with FictionJunction and Kalafina. She is managed by Spacecraft Group.
Keiko began singing, along with many other familiar names (Wakana, Kaori, Yoshida Yuuki, Ito Ayaka), when she became sponsored by Spacecraft (a talent agency in Japan). She performed alongside these other girls in many types of small concerts.
Her recording career began when she first worked with the already famous composer, Yuki Kajiura, on an insert song for the Tsubasa CHRoNiCLE anime. The song, "Kaze no Machi he," (風の街へ) featured a vocal style Yuki Kajiura had not focused much on in the past, an alto range. This made Keiko very unique in comparison to the other few dozen vocalists that were credited alongside Yuki Kajiura, and earned the name FictionJunction KEIKO, an honor only a handful of the collaborations can boast about.
After recording and releasing this song, Keiko teamed up with a friend named Ito Ayaka to form the duo "Itokubo". They recorded a song for a Japanese video game together ("Beautiful Katamari") and did a number of shows for about two years, before they quit in January of 2007.
Sometime in mid-2007, Yuki Kajiura was asked to do the soundtrack for the Kara no Kyoukai series of movies. Being a different sort of project - a series of movies, all with different themes, rather than a single anime series, all connected by the same music - she decided to take a different approach and held auditions for a group she named "Kalafina," who would do the ending themes to each movie. Keiko auditioned and was one of two vocalists to become a part of Kalafina, the other being another FictionJunction vocalist, Wakana.
The members of Kalafina are also famous throughout the world. In 2009, they participated at an anime festival in Boston, before they started their first oneman tour in 2010, with stops at Taipei, Shanghai and Hong Kong. Then, they joined in several anime events in LA, in Singapore, in Malaysia, in Germany and in Indonesia. In May of 2013, they perform at the Anime Central 2013, the third largest North American anime convention, and they also completed their Arena live concert at Kobe World Memorial Hall and prestigious Nippon Budokan respectively.
Currently, Keiko works with both Kalafina and FictionJunction.