The foundation for ONE OK ROCK began when Toru, then a high school student, wanting to start a band. Toru told his friend Ryota, who had been in Heads with him, to learn the Bass and asked Alex to join. After seeing Taka, a vocalist, perform in a cover band, Toru saw him as the best possible candidate for a vocalist in their band, and insisted that he join. Tomoya, the last member to join, joined ONE OK ROCK as a drummer in 2007.[3] Tomoya had played with band on all their albums but only became an official member when they debuted.
The band name, ONE OK ROCK, came from "one o'clock," the time that the band used to practice on weekends. However, noticing that the Japanese language made no distinction between r's and l's, they changed "o'clock" to "o'crock" (or "o'krock") which then became separated to become "ok rock".[3]
* Takahiro Moriuchi (森内 寛貴, Moriuchi Takahiro?, born April 17, 1988 in Tokyo) - Vocals. Son of Shinichi Mori.
* Toru (born December 7, 1988 in Osaka) - guitar and he partially sings some of the groups songs.
* Alexander Onizawa[4] (born March 19, 1988 in San Francisco) - guitar. Officially left band as of May 2009.
* Ryota (born September 4, 1989 in Osaka) - bass
* Tomoya (born June 27, 1987 in Hyogo) - drums
