The standard grips this chord is usually shown with.
Cm9 is C, Eb, G, Bb and D — Cm7 with the ninth stacked above it.
It sounds warm, and considerably richer than an m7. The standard voicing for a ii chord once the plain one has been played enough.

| C | Eb | G | Bb | D |
|---|---|---|---|---|
| 1 | ♭3 | 5 | ♭7 | 9 |
Pre-dominant or minor tonic — an m7’s job with more colour.
Also written Cmin9, C-9 or C minor 9. The same chord either way; which spelling you meet depends on who wrote the chart.
Cm9 in 2nd inversion puts G in the bass instead of C, the 5th of the chord. The notes are the same; what changes is what the bass line does, which is most of why you would reach for it — it lets the lowest voice move by step where the root would have jumped.
One of Cm9’s 9 common shapes does this: xx5746.
Start with xx5746 — no barre and low, at the 4th fret. 1 of the 9 shapes here sits in open position. 6 of the 9 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x3133x | 1st fret | C, root position | D | barred |
| x30343 | open position | C, root position | G | barred |
| x55546 | 4th fret | D, 9th in the bass | Bb | barred |
| xx5746 | 4th fret | G, 2nd inversion | Bb | all fretted |
| 86x786 | 6th fret | C, root position | Bb | all fretted |
| x68788 | 6th fret | Eb, 1st inversion | C | barred |
| 8-10-8-8-8-10 | 8th fret | C, root position | D | barred |
| 11-13-12-12-13-11 | 11th fret | Eb, 1st inversion | Eb | all fretted |
| x-15-13-15-15-15 | 13th fret | C, root position | G | barred |
The same notes rebuilt from scratch give 4 shell, 13 drop 2, 8 drop 3, 14 rootless and 3 open string voicings, each on its own page.
Tensions. A shell of Cm9, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (F) and the 13 (A).
How you get to it. The turn that lands on Cm9 is Dm7♭5 to G7♭9: the ii and the V of C minor, which is where a minor tonic is usually arrived at rather than simply begun on.
In which keys. Every note of Cm9 belongs to C minor (the i, the tonic), Eb major (the vi, the submediant), G minor (the iv, the subdominant) and Bb major (the ii, the supertonic).
Every note of Cm9 is in C dorian and C natural minor.
Change one note of Cm9 and you have Cm69 (the flat seventh becomes a sixth), Cm7 (drop the ninth), Cm11 (add the fourth), CmMaj9 (the flat seventh becomes a major seventh), Cmadd9 (drop the flat seventh) or C9 (the minor third becomes a major third).
Cm9 is a minor chord — root, minor third, fifth. Minor chords on every root.
On Cm9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.