Best known as principal songwriter of the band Kannivalism, guitarist Kei produced a number of electronica-influenced solo releases, quite different from his work with the band, while they were on enforced hiatus between 2008 and 2010. He was born Kei Hamada on August 12, 1984 in Zama, Japan; his given name is written with a character representing a jade tablet ritually worn by feudal lords in ancient China, and is unrelated to the kei of visual kei, which is usually translated "system."

This precocious talent formed his first band, Clarity, at the tender age of 14, but it was with Kannivalism that he first tasted fame in 2001. In its original incarnation, the group lasted barely six months before disbanding, but Kei and vocalist Ryo went on to form Baroque, with which they achieved considerable success, signing to a major and even getting to play at the legendary Nippon Budokan. When Baroque split in 2005, the two re-formed Kannivalism. Their industry kudos quickly clinched them another major-label deal, this time with Avex Trax, and early in 2007 they released their debut album, Nu Age, which had a quirky, jazzy, pop-punk sound.

The band was working on its second album when, in 2008, Ryo was hospitalized, suffering from a crippling depression that had plagued him for years. When it became clear that he was not going to recover quickly, the band reluctantly went on hiatus and Kei, finding himself at loose ends, retreated to the studio to work on his own material. Heavily influenced by mid-period Radiohead and Japanese duo the Boom Boom Satellites, he went back to the electronica sound Baroque had flirted with, ambitiously aiming to combine it with rock in a way that had never been done before. Inspiration flowed, and in less than a year, he had produced an album's worth of material, which Avex offered to release through its subsidiary Cutting Edge.

His debut single The Primary was epic pop/rock shot through with electronic elements and backed with a frenetic drum'n'bass beat, while the follow-up, Vesperbell, had an orchestral arrangement and a jaunty, playful feel. These singles were followed in March 2009 by the album Silk Tree, which combined arpeggiated guitar figures with synthesized melody lines, computer-generated sounds, high-energy programmed club beats, lyrics mostly in English, and even classical music influences, with several songs featuring soothing, hauntingly beautiful arrangements for piano, strings, and oboe. A special edition was also released which included club remixes and a DVD detailing Kei's creative process in the studio. Just six months later, Kei had already produced a new mini-album, For a Fleeting Moment. At the same time as its release, it was announced that Ryo had recovered and that Kannivalism would be resuming activities, essentially putting a stop to Kei's solo career. But on Kannivalism's second album, 2010's Helios, the influence of his solo works could be keenly felt; it had much more in common with these than with the band's first album. ~ John D. Buchanan, Rovi