Ninth Chord - 6/9 Chord

6/9 Chord

The 6/9 chord is a pentad in which a major triad is extended with a sixth and 9th above the root, but no seventh, thus: C6/9 is C,E,G,A,D. It is not a tense chord requiring resolution, and is considered a substitute for the tonic in jazz. Its constituent notes are those of the pentatonic scale.

Heinrich Schenker, though he allowed the substitution of the dominant seventh, leading-tone, and leading tone half-diminished seventh chords, rejected the concept of a ninth chord on the basis that only that on the fifth scale degree (V9) was admitted and that inversion was not allowed of the ninth chord.