The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
Bb6 is Bb, D, F and G — Bb with a major sixth added on top.
It sounds warm, and finished without being sweet. It closes a tune as firmly as the triad does but without the maj7’s shine, which is why so many standards end on one.

| Bb | D | F | G |
|---|---|---|---|
| 1 | 3 | 5 | 6 |
Tonic — an ending chord.
Also written Bbmaj6, BbM6 or Bb major 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.
Bb6 has 10 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 15th — every inversion the chord has: Bb in the bass, D 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 6x576x — no barre and low, at the 5th fret. None of the shapes for Bb6 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 6 of the 11 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x13333 | 1st fret | Bb, root position | G | barred |
| x53333 | 3rd fret | D, 1st inversion | G | barred |
| 655333 | 3rd fret | Bb, root position | G | barred |
| 353363 | 3rd fret | G, 6th in the bass | G | barred |
| 650066 | 5th fret | Bb, root position | Bb | barred |
| 6x576x | 5th fret | Bb, root position | F | all fretted |
| 6x8786 | 6th fret | Bb, root position | Bb | all fretted |
| 68x786 | 6th fret | Bb, root position | Bb | all fretted |
| x-x-8-10-8-10 | 8th fret | Bb, root position | D | all fretted |
| x-13-12-12-11-x | 11th fret | Bb, root position | Bb | all fretted |
| x-13-15-15-15-15 | 13th fret | Bb, root position | G | barred |
The same notes rebuilt from scratch give 7 shell, 15 drop 2 and 6 open string voicings, each on its own page.
Tensions. A shell of Bb6, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (C) and the #11 (E).
How you get to it. The turn that lands on Bb6 is Cm7 to F7 — the ii and the V of Bb — and F7 shares its third and seventh with Cm7, so the hand barely moves between them.
In which keys. Every note of Bb6 belongs to C minor (the ♭VII), D minor (the ♭VI), Eb major (the V), F major (the IV), G minor (the ♭III) and Bb major (the I).
Every note of Bb6 is in Bb major pentatonic, Bb major, Bb lydian, Bb mixolydian and Bb lydian dominant.
Change one note of Bb6 and you have Bb (drop the sixth), Bbmaj7 (the sixth becomes a major seventh), Bbm6 (the major third becomes a minor third), Bbadd9 (the sixth becomes a ninth), Bb69 (add the ninth) or Bb7 (the sixth becomes a flat seventh).
Bb6 is a major chord — root, major third, fifth. Major chords on every root.
On Bb6’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.