CN BLUE is an acronym for Code Name: Burning, Lovely, Untouchable, Emotional. Each adjective refers to each individual member of the four-man rock band. They made their debut with the album Now or Never in Japan in 2009 under AI Entertainment, followed by their Korean debut in 2010 with FNC Music. In 2011, the group made their major label debut in Japan with the song In My Head. Kwon Kwang Jin was the original bassist of the band but left after their first Japanese album. He was replaced by Lee Jung Shin. The group has become popular in both Japan and Korea.