Kawatani grew to like music when he was eight years old, when he heard
T.M.Revolution's song "High Pressure" (1997). He began composing music while he was a university student at the
Tokyo University of Agriculture and Technology. There, he met Masao Wada (currently known as Gesu no Kiwami Otome's bassist Kyūjitsu Kachō) at the
light music club. In April 2009, Kawatani formed the band
Indigo la End, mostly performing live performances in the
Shinjuku, Shimokitazawa and
Shibuya areas of Tokyo. Indigo la End released their debut
extended play Sayōnara, Subarashii Sekai in April 2012, through the independent label
Space Shower Music. In May 2012, Kawatani asked members of other bands who played at the Shimokitazawa Era live house to form a musical project together, as a fun activity outside of their regular projects, and called this band
Gesu no Kiwami Otome. Kawatani continued to release music with Indigo la End, with their second extended play
Nagisa nite in September 2012 and their first album
Yoru ni Mahō o Kakerarete in February 2013. A month after their debut album, Gesu no Kiwami Otome also debuted through Space Shower Music, releasing the extended play
Dress no Nugikata. In December 2013, both of Kawatani's bands were signed to
Warner sub-label
Unborde. Both musical units released their major label debut releases on April 2, 2014:
Minna Normal for Gesu no Kiwami Otome and
Ano Machi Record for Indigo la End. In August 2014, Gesu no Kiwami's song "
Ryōkiteki na Kiss o Watashi ni Shite" was used as the drama
Around 30-chan: Mushūsei's opening theme song and released as a single. It reached number four on the
Billboard Japan Hot 100 chart, and was certified gold by the
Recording Industry Association of Japan. The band's debut album
Miryoku ga Sugoi yo (2014) reached number four on Oricon's album charts, and their second,
Ryōseibai (2016), reached number one, after several commercially successful singles released in 2015: "Watashi Igai Watashi ja Nai no", "Romance ga Ariamaru" and "Otonatic". In 2014, Kawatani composed songs for musicians outside of his two bands for the first time, when he gave the boyband
SMAP two songs for their album
Mr. S. Kawatani worked with the band again in 2015, on their single "Ai ga Tomaru made wa", and has also worked with
Tomohisa Yamashita, and the girl group
Team Syachihoko on their single "Shampoo Hat" (2014). == Personal life ==