Allan Holdsworth, a jazz and progressive-rock guitarist with many admirers across music genres, died on Sunday, April 16, according to a Facebook post from his daughter, Louise Holdsworth. He was 70. Holdsworth’s career began in the 1970s, when he played with various jazz-fusion and progressive-rock bands, including Soft Machine and Tempest. He was an early member of U.K., a British supergroup founded by Yes drummer Bill Bruford and King Crimson singer and bassist John Wetton, though he left shortly after the band’s self-titled debut album was released. He would go on to release over a dozen solo albums, many of which feature the SynthAxe, a rare instrument that controls synthesizers with keys and string triggers. Guitarists including Eddie Van Halen, Tom Morello, and Frank Zappa cited Holdsworth as a musical influence.