Kazuyoshi Saito (June 22, 1966) is a Japanese singer-songwriter who performs in the folk-rock genre. He is also one-half of the rock duo Mannish Boys and a member of the supergroup Curling Sitones. Born in Mibu, Tochigi, he began playing the guitar in elementary school and soon developed a taste for hard rock acts such as Kiss, Aerosmith, and Van Halen. Preceded by the single "Boku no Mita Beatles wa TV no Naka," his studio debut Aoi Sora no Shita... was released in 1993 to great critical acclaim. In the following years, albums like Suteki na Nioi no Sekai (1994), Fire Dog (1996), and Dilemma (1997) helped established him as one of the most innovative and authentic acts in the J-rock scene. However, his popularity reached new levels during 2007 and 2008 after his singles "Wedding Song" and "Ai ni Kite" were featured in TV commercials. From there on, he became a regular presence on the Japanese Top 10 with titles like I Love Me (2007), Are You Ready? (2010), and 45 Stones (2011) and continued to contribute original music to numerous anime series. Almost a decade after its release, his 1997 track "Uta Utai No Ballad" was used as the main theme of the 2017 anime film Lu Over the Wall. In 2018, Kazuyoshi Saito scored his first Number 1 record with Toys Blood Music. He followed this success with the albums 202020 (2020) and 55 Stones (2021), both of which cracked the Top 5 of the Oricon charts.