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.
Gmaj9 is G, B, D, F# and A — Gmaj7 with the ninth stacked above it.
It sounds a maj7 with more air in it. The ninth argues with nothing here, so it works anywhere a maj7 does.

| G | B | D | F# | A |
|---|---|---|---|---|
| 1 | 3 | 5 | 7 | 9 |
Tonic — an extended resting chord.
Also written GM9, GΔ9, Gma9 or G major 9. 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.
Gmaj9 has 6 of them, on strings 6-5-4-3-2-1, strings 5-4-3-2-1 and strings 6-4-3-2-1, from the 2nd fret up to the 4th — every inversion the chord has: G in the bass, B in the bass, D in the bass, F# in the bass and A in the bass. The one to learn first is the G shape at the 2nd fret, which is the easiest grip here.
3 of them sit on strings 5-4-3-2-1, 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 300002 — no barre and 4 open strings. 1 of the 12 shapes here sits in open position. 6 of the 12 need a barre. Together they cover the neck from the 2nd fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 300002 | open position | G, root position | F# | 4 open strings |
| 324232 | 2nd fret | G, root position | F# | barred |
| 354435 | 3rd fret | G, root position | A | all fretted |
| xx4435 | 3rd fret | F#, 3rd inversion | A | all fretted |
| xx5475 | 4th fret | G, root position | A | all fretted |
| 755775 | 5th fret | B, 1st inversion | A | barred |
| x-10-7-7-7-7 | 7th fret | G, root position | B | barred |
| x-10-9-11-10-x | 9th fret | G, root position | A | all fretted |
| 10-10-9-11-10-x | 9th fret | D, 2nd inversion | A | barred |
| x-12-12-12-12-14 | 12th fret | A, 9th in the bass | F# | barred |
| x-x-12-14-12-14 | 12th fret | D, 2nd inversion | F# | all fretted |
| 15-12-12-12-12-14 | 12th fret | G, root position | F# | barred |
The same notes rebuilt from scratch give 3 shell, 12 drop 2, 9 drop 3 and 14 rootless voicings, each on its own page.
Tensions. A shell of Gmaj9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (C#) and the 13 (E).
How you get to it. The turn that lands on Gmaj9 is Am7 to D7 — the ii and the V of G — and D7 shares its third and seventh with Am7, so the hand barely moves between them.
In which keys. Every note of Gmaj9 belongs to D major (the IV, the subdominant), E minor (the ♭III), G major (the I, the tonic) and B minor (the ♭VI).
Every note of Gmaj9 is in G major and G lydian.
Change one note of Gmaj9 and you have Gmaj7 (drop the ninth), Gmaj11 (add the fourth), Gmaj13 (add the sixth), GmMaj9 (the major third becomes a minor third), Gadd9 (drop the major seventh) or G69 (the major seventh becomes a sixth).
Gmaj9 is a major chord — root, major third, fifth. Major chords on every root.
On Gmaj9’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.