D=OUT began activities in December of 2006. Following Kouki's former band, Mist of Rouge's, disbandment in 2003 and an unsuccessful solo career, he teamed up with Ibuki (guitar), Hikaru (guitar), Reika (bass) and Minase (drums) to start a new band.
Only five days after the announcement of D=OUT's formation, the five members played their first concert on December 29th at Holiday Shinjuku with a number of concerts at Ikebukuro Cyber and Holiday Shinjuku after that.
On April 3, 2007 their first song, Flashback, was released as a free single. Following more concerts in Tokyo their first maxi single, Heisei Bubble, hit stores. Released in three versions, the single sold out, thanks to heavy surface promotion, and a second press came in August.
Their second maxi single, Shirohata Sengen, followed soon after and the band, having become part of the popular indie label Speed Disk, released their third single, Bara iro no jinsei, on December 19th.
2008 proved to be a busy year for D=OUT. Their first single of the year, Bankoku, dai toukyou / Akai kasa to anata, was released in February. In the spring they put out a mini-album, Rouman doumyakuteki chabangeki, which was followed that summer by their debut album, Zipang. That fall Zipang became their first European release.
Now in 2009, showing their interest again in their growing overseas fan base, D=OUT will embark on their European tour in April, when they will play in Spain, France, Germany and the Netherlands.