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.
Cm6 is C, Eb, G and A — Cm with a major sixth added on top.
It sounds bittersweet — minor underneath, major on top. The major sixth over a minor triad comes from the melodic minor, and it is the classic jazz minor tonic.

| C | Eb | G | A |
|---|---|---|---|
| 1 | ♭3 | 5 | 6 |
Minor tonic — an ending chord in a minor key.
Also written Cmin6, C-6 or C minor 6. 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.
Cm6 has 2 of them, on the bottom four strings and the middle four strings, from the 3rd fret up to the 5th — all in one inversion, so the bass note never moves. The one to learn first is the A shape at the 3rd fret, which is the easiest grip here.
Start with x3524x — no barre and down at the nut. None of the shapes for Cm6 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 3 of the 9 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x31213 | 1st fret | C, root position | G | all fretted |
| x3524x | 2nd fret | C, root position | Eb | all fretted |
| x35x45 | 3rd fret | C, root position | A | all fretted |
| xx5545 | 4th fret | G, 2nd inversion | A | barred |
| x6758x | 5th fret | Eb, 1st inversion | G | all fretted |
| 8x7888 | 7th fret | C, root position | C | barred |
| 8-10-10-8-10-8 | 8th fret | C, root position | C | barred |
| x-x-10-12-10-11 | 10th fret | C, root position | Eb | all fretted |
| x-15-13-14-13-15 | 13th fret | C, root position | G | all fretted |
The same notes rebuilt from scratch give 6 shell, 15 drop 2 and 9 drop 3 voicings, each on its own page.
Tensions. A shell of Cm6, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (D) and the 11 (F).
How you get to it. The turn that lands on Cm6 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 Cm6 belongs to G minor (the iv, the subdominant) and Bb major (the ii, the supertonic).
Every note of Cm6 is in C dorian, C melodic minor and C half-whole diminished.
Change one note of Cm6 and you have Cm (drop the sixth), Cdim7 (the fifth becomes a flat fifth), Cm69 (add the ninth), Cm7 (the sixth becomes a flat seventh), CmMaj7 (the sixth becomes a major seventh) or Cmadd9 (the sixth becomes a ninth).
Cm6 is a minor chord — root, minor third, fifth. Minor chords on every root.
On Cm6’s sound and use this page follows Mark Levine, The Jazz Piano Book (Sher Music, 1989). 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.