Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
GmMaj9 is G, Bb, D, F# and A — GmMaj7 with the ninth added on top.
It sounds the same unease with more colour over it. The ninth softens the edge without resolving anything.

| G | Bb | D | F# | A |
|---|---|---|---|---|
| 1 | ♭3 | 5 | 7 | 9 |
Minor tonic — melodic minor, extended.
Also written GmM9, Gm(maj9) or G-Δ9. The same chord either way; which spelling you meet depends on who wrote the chart.
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
GmMaj9 has 3 of them, on the bottom four strings, the top four strings and the middle four strings, from open position up to the 8th — all in one inversion, so the bass note never moves. The one to learn first is the G shape at the nut.
Start with 3142xx — no barre and down at the nut. 1 of the 8 shapes here sits in open position. 4 of the 8 need a barre. Together they cover the neck from the 1st fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 300332 | open position | G, root position | F# | barred |
| 31x232 | 1st fret | G, root position | F# | all fretted |
| 3142xx | 1st fret | G, root position | A | all fretted |
| 354335 | 3rd fret | G, root position | A | barred |
| 555776 | 5th fret | A, 9th in the bass | Bb | barred |
| xx7076 | 6th fret | A, 9th in the bass | Bb | 1 open string |
| x-10-8-11-10-x | 8th fret | G, root position | A | all fretted |
| 10-13-12-11-10-10 | 10th fret | D, 2nd inversion | D | barred |
The same notes rebuilt from scratch give 5 drop 2, 4 drop 3, 13 rootless and 2 open string voicings, each on its own page.
Tensions. A shell of GmMaj9, 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 GmMaj9 is Am7♭5 to D7♭9: the ii and the V of G minor, which is where a minor tonic is usually arrived at rather than simply begun on.
Every note of GmMaj9 is in G harmonic minor and G melodic minor.
Change one note of GmMaj9 and you have Gmaj9 (the minor third becomes a major third), Gm69 (the major seventh becomes a sixth), Gm9 (the major seventh becomes a flat seventh), GmMaj7 (drop the ninth), GmMaj11 (add the fourth) or Gmadd9 (drop the major seventh).
GmMaj9 is a minor chord — root, minor third, fifth. Minor chords on every root.
On GmMaj9’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.