C69 is C, E, G, A and D — with the ninth added as well.
It sounds wide and entirely at rest. The modern way to voice a tonic when a triad is too bare and a maj7 too pointed.
Tonic — it commits to nothing.
Also written C6/9, C6add9 or C six nine.
Where a tune’s home chord is written as a major seventh or sixth, C69 is often played instead. It is C major’s sixth chord with one note raised a whole step, root to ninth.
Listen for: The ii’s root holds through the V as its fifth and stays on as the ninth of the I. On the sixth chord it falls a whole step to the root.
In which keys. Every note of C69 belongs to C major, D minor, E minor, F major, G major and A minor.
C69 is every note of the C major pentatonic, and nothing else. It also sits inside C major, C mixolydian, C lydian and C lydian dominant.
Each of those is a page: the scale across the neck, and the chords it harmonises into — which is where C69 sits in it. Every scale.
Change one note of C69 and you have (the sixth becomes the major seventh), (add the major seventh), (the major third becomes the minor third), (drop the sixth), (drop the ninth) or (the sixth becomes the flat seventh).
C69 is a major chord — root, major third, fifth. Major chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.