Zazen Boys is a Japanese band that emerged from the breakup of Number Girl, one of the most influential rock groups in Japanese music history. The group formed in Tokyo, Japan, in 2003, founded by former Number Girl guitarist and vocalist Shutoku Mukai. Zazen Boys carved out a unique space in the indie rock, math rock, and new wave scenes. The group made a name for itself due to its distinctive sound, incorporating a diverse range of influences including Buddhist chants, hip-hop, funk, punk, and improvisational jazz. The initial lineup of Zazen Boys included Shutoku Mukai, former Number Girl drummer Ahito Inazawa, Art-School bassist Hidekazu Hinata, and guitarist Sō Yoshikane. They released their self-titled debut album in 2004, accompanied by the popular single "Hantōmei Shōjo Kankei." Their second album, Zazen Boys II, was released the same year and received critical acclaim. In 2005, Atsushi Matsushita joined, replacing Ahito Inazawa. The band continued to evolve, releasing their third album, Zazen Boys III, in 2006; this release featured more experimental and improvisational elements. This period also saw the release of various live recordings and online-exclusive albums. After more lineup changes, the group released Zazen Boys 4 in 2008, followed by Stories in 2012. The year 2024 saw the release of the album Rando, featuring the group's new bassist Miya, formerly of the band Bleach. Rando peaked at number 9 on the Oricon Albums Chart.