When a clavichord key is pressed, a small metal tangent strikes a string and remains in contact with it for as long as the key is held down. By applying a rocking pressure up and down the key with the finger, a performer can slightly alter the vibrating length of the string itself, producing a vibrato quality known as Bebung. While the vibrato on fretless string instruments such as the violin typically oscillates in pitch both above and below the nominal note, clavichord Bebung can only produce pitches above the note.
Bebung was often not explicitly indicated in sheet music; the assumption was that, like other ornaments, Bebung was to be applied at the performer's discretion. Where Bebung is indicated, it appears as a series of dots written above or below a note, with the number of dots indicating the number of movements of the finger.