The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
Abm69 is Ab, Cb, Eb, F and Bb — Abm6 with the ninth added as well.
It sounds cool and entirely at rest. No seventh, so nothing leans: a common last chord of a minor tune.

| Ab | Cb | Eb | F | Bb |
|---|---|---|---|---|
| 1 | ♭3 | 5 | 6 | 9 |
Minor tonic — nothing in it is pulling.
Also written Abm6/9, Abmin6/9 or Ab-6/9. The same chord either way; which spelling you meet depends on who wrote the chart.
The same operation one voice further down: the third voice from the top falls an octave and becomes the bass.
That leaves a bigger hole under the top three notes, so a string gets skipped: the muted string in the middle is the shape, not a mistake.
Abm69 has 9 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 12th — every inversion the chord has: Ab in the bass, Cb in the bass, F in the bass and Bb in the bass. The one to learn first is the Bb shape at the nut.
5 of them sit on strings 5-3-2-1, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with 4233xx — no barre and down at the nut. None of the shapes for Abm69 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 5 of the 8 need a barre. Together they cover the neck from the 2nd fret to the 11th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 4233xx | 2nd fret | Ab, root position | Bb | all fretted |
| x23344 | 2nd fret | Cb, 1st inversion | Ab | all fretted |
| 4x3446 | 3rd fret | Ab, root position | Bb | barred |
| 4x6466 | 4th fret | Ab, root position | Bb | barred |
| xx6466 | 4th fret | Ab, root position | Bb | barred |
| x66466 | 4th fret | Eb, 2nd inversion | Bb | barred |
| 766866 | 6th fret | Cb, 1st inversion | Bb | barred |
| x-11-9-10-11-x | 9th fret | Ab, root position | Bb | all fretted |
The same notes rebuilt from scratch give 3 shell, 13 drop 2 and 13 rootless voicings, each on its own page.
Tensions. A shell of Abm69, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (Db).
How you get to it. The turn that lands on Abm69 is Bbm7♭5 to Eb7♭9: the ii and the V of Ab minor, which is where a minor tonic is usually arrived at rather than simply begun on.
In which keys. Every note of Abm69 belongs to Eb minor (the iv, the subdominant) and F# major (the ii, the supertonic).
Every note of Abm69 is in Ab dorian and Ab melodic minor.
Change one note of Abm69 and you have Abm6 (drop the ninth), Abm9 (the sixth becomes a flat seventh), AbmMaj9 (the sixth becomes a major seventh), Abmadd9 (drop the sixth) or Ab69 (the minor third becomes a major third).
Abm69 is a minor chord — root, minor third, fifth. Minor chords on every root.
On Abm69’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.