"Vivid Colors") is the seventh album by Mucc, released on December 6, 2006 in Japan and on February 23, 2007 in Europe.

The album presents a more commercial sound, showing clear influences of pop rock.

Gokusai reached number 22 on the Oricon Albums Chart.

[1] Mucc re-recorded of "Utagoe" and "Ryūsei" for their 2017 self-cover album Koroshi no Shirabe II This is Not Greatest Hits.

"Utagoe", "Gerbera", and "Ryūsei" were covered by Kishidan, Sukekiyo and Plastic Tree respectively, for the 2017 Mucc tribute album Tribute of Mucc -En-.