One OK Rock (stylized in all caps as ONE OK ROCK), is a Japanese rock band, formed in Tokyo, Japan in 2005. The band currently consists of Takahiro Moriuchi (vocalist), Toru Yamashita (guitarist, bandleader), Ryota Kohama (bassist), and Tomoya Kanki (drummer). They have been playing many different styles of music, with songs ranging from alternative rock to emo to post-hardcore to pop rock.The band's name comes from "one o'clock", the time that the band used to practice their music on weekends. They chose to play at one o'clock in the morning because it was cheaper to use the rehearsal space during such hours. However, noticing that the Japanese language made no distinction between R's and L's, "O'CLOCK" transformed into "O'CROCK" or "O'KROCK", which later transformed into "OK ROCK". In addition, One OK Rock can be expressed as "10969" (wan-ō-ku-ro-ku). The band uses both Japanese and English lyrics in their songs.
One OK Rock has won Classic Rock Roll of Honour Awards for Eastern Breakthrough Male Band in 2016, and Rock Sound Awards for Best International Band in 2017. The band was also nominated for two Alternative Press Music Awards – Best International Band in 2016 and Best Breakthrough Band in 2017.