An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful.
CmMaj9 is C, Eb, G, B and D — CmMaj7 with the ninth added on top.
It sounds the same unease with more colour over it. The ninth softens the edge without resolving anything.

| C | Eb | G | B | D |
|---|---|---|---|---|
| 1 | ♭3 | 5 | 7 | 9 |
Minor tonic — melodic minor, extended.
Also written CmM9, Cm(maj9) or C-Δ9. The same chord either way; which spelling you meet depends on who wrote the chart.
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
CmMaj9 has 5 of them, on the bottom four strings, the middle four strings, strings 6-5-4-3-2, the top four strings and strings 6-4-3-2, from the 2nd fret up to the 6th — every inversion the chord has: G in the bass, B in the bass and D in the bass. The one to learn first is the B shape at the 2nd fret, which is the easiest grip here.
Start with x3143x — no barre and down at the nut. 1 of the 8 shapes here sits in open position. 3 of the 8 need a barre. Together they cover the neck from the 1st fret to the 12th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x30443 | open position | C, root position | G | 1 open string |
| x3143x | 1st fret | C, root position | D | all fretted |
| 365433 | 3rd fret | G, 2nd inversion | G | barred |
| 86x708 | 6th fret | C, root position | C | 1 open string |
| 86x787 | 6th fret | C, root position | B | all fretted |
| 8697xx | 6th fret | C, root position | D | all fretted |
| 8-10-9-8-8-10 | 8th fret | C, root position | D | barred |
| 10-10-10-12-12-11 | 10th fret | D, 9th in the bass | Eb | barred |
The same notes rebuilt from scratch give 3 shell, 5 drop 2, 3 drop 3 and 13 rootless voicings, each on its own page.
Tensions. A shell of CmMaj9, 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 CmMaj9 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.
Every note of CmMaj9 is in C harmonic minor and C melodic minor.
Change one note of CmMaj9 and you have Cmaj9 (the minor third becomes a major third), Cm69 (the major seventh becomes a sixth), Cm9 (the major seventh becomes a flat seventh), CmMaj7 (drop the ninth), CmMaj11 (add the fourth) or Cmadd9 (drop the major seventh).
CmMaj9 is a minor chord — root, minor third, fifth. Minor chords on every root.
On CmMaj9’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.