Since Osaka's Janne Da Arc took a sabbatical in 2006, all of the phenomenally successful group's five members have pursued various musical projects. While singer Yasu's new band, Acid Black Cherry, has been the most high-profile offshoot, bassist Ka-yu has also found some success, developing his songwriting chops -- not to mention his English-language skills -- over two mini-albums. Ka-yu's debut solo effort, Solid Beat, was released in summer 2007 under his actual name, Kazuyuki Matsumoto, and later that year he followed up with Solid Beat II. Both albums featured lyrics entirely in English penned by outside collaborators. Musically, the two discs saw Ka-yu move in a punkier direction compared to Janne Da Arc, although the metallic riffs and frenzied guitar solos will be familiar to fans of that band. In addition to recording, Ka-yu has also toured (backed by a drummer and guitarist) throughout Japan. In 2007 Ka-yu was the opening act at Japan's annual Loud Park festival at the Saitama Super Arena, sharing the bill alongside the likes of Trivium, Machine Head, and Marilyn Manson. As is de rigueur with any Japanese artist with a young fan base, Ka-yu also released a photo book, Solid Beat Zero, in March 2008, featuring photos of the generously tattooed musician -- whose look might be described as neo-goth punk -- performing live, backstage, and in the studio. Ka-yu also launched his own fashion brand, Solid Beat, in spring 2009.