The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
Bbm6 is Bb, Db, F and G — Bbm 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.

| Bb | Db | F | G |
|---|---|---|---|
| 1 | ♭3 | 5 | 6 |
Minor tonic — an ending chord in a minor key.
Also written Bbmin6, Bb-6 or Bb minor 6. 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.
Bbm6 has 10 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 14th — every inversion the chord has: Bb in the bass, Db in the bass, F in the bass and G 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 x13x23 — no barre and down at the nut. None of the shapes for Bbm6 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 9 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x13x23 | 1st fret | Bb, root position | G | all fretted |
| xx3323 | 2nd fret | F, 2nd inversion | G | barred |
| x4536x | 3rd fret | Db, 1st inversion | F | all fretted |
| 6x5666 | 5th fret | Bb, root position | Bb | barred |
| 688686 | 6th fret | Bb, root position | Bb | barred |
| x-x-8-10-8-9 | 8th fret | Bb, root position | Db | all fretted |
| x-13-11-12-11-13 | 11th fret | Bb, root position | F | all fretted |
| x-13-15-12-14-x | 12th fret | Bb, root position | Db | all fretted |
| x-x-15-15-14-15 | 14th fret | F, 2nd inversion | G | barred |
The same notes rebuilt from scratch give 7 shell and 14 drop 2 voicings, each on its own page.
Tensions. A shell of Bbm6, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (C) and the 11 (Eb).
How you get to it. The turn that lands on Bbm6 is Cm7♭5 to F7♭9: the ii and the V of Bb minor, which is where a minor tonic is usually arrived at rather than simply begun on.
In which keys. Every note of Bbm6 belongs to F minor (the iv, the subdominant) and Ab major (the ii, the supertonic).
Every note of Bbm6 is in Bb dorian, Bb melodic minor and Bb half-whole diminished.
Change one note of Bbm6 and you have Bbm (drop the sixth), Bbdim7 (the fifth becomes a flat fifth), Bbm69 (add the ninth), Bbm7 (the sixth becomes a flat seventh), BbmMaj7 (the sixth becomes a major seventh) or Bbmadd9 (the sixth becomes a ninth).
Bbm6 is a minor chord — root, minor third, fifth. Minor chords on every root.
On Bbm6’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.