Accidental (music) felt it was obvious that the accidental should continue. The older practice continued in use well into the 18th century by many composers, notably Johann Sebastian Bach. The newer convention did not achieve general currency until early in the 19th century. Accidental (music) In music, an accidental is a note of a pitch (or pitch class) that is not a member of the scale or mode indicated by the most recently applied key signature. In musical notation, the sharp (), flat (), and natural () symbols, among others, mark such notes—and those symbols are also called accidentals. In the measure
Key signature Key signature In musical notation, a key signature is a set of sharp (), flat (), and rarely, natural () symbols placed together on the staff. Key signatures are generally written immediately after the clef at the beginning of a line of musical notation, although they can appear in other parts of a score, notably after a double barline. A key signature designates notes that are to be played higher or lower than the corresponding natural notes and applies through to the end of the piece or up to the next key signature. A sharp symbol on a line or