Karaoke, a form of entertainment in which amateur performers sing songs using pre-recorded music, was popularized by Japanese musician Daisuke Inoue in the 1970s. Inoue invented a coin-operated music player in 1971 after fans requested recordings of his performances-they wanted to sing along with the music on a company retreat. He never patented the karaoke technology and thus forfeited(失う)a potential fortune.