Straight-ahead jazz is a jazz music style from the period between bebop and the 1960s' styles of Wayne Shorter and Herbie Hancock. It is considered the lingua franca of jam sessions, and can usually be contrasted with smooth jazz. It has the following characteristics: * A walking bass * A swing 4/4 time signature in the drums * In the piano, syncopated chords in the left hand, and melodic, mostly single-note soloing in the right hand * A head followed by a solo by each melody instrument, and sometimes drums and bass, followed by a reprise of the head