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.
Gm9 is G, Bb, D, F and A — Gm7 with the ninth stacked above it.
It sounds warm, and considerably richer than an m7. The standard voicing for a ii chord once the plain one has been played enough.

| G | Bb | D | F | A |
|---|---|---|---|---|
| 1 | ♭3 | 5 | ♭7 | 9 |
Pre-dominant or minor tonic — an m7’s job with more colour.
Also written Gmin9, G-9 or G minor 9. 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.
Gm9 has 4 of them, on the bottom four strings, the middle four strings and the top four strings, from open position up to the 13th — all in one inversion, so the bass note never moves. The one to learn first is the G shape at the nut, which is the easiest grip here.
Start with xx7066 — no barre and 1 open string. 1 of the 9 shapes here sits in open position. 5 of the 9 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 300331 | open position | G, root position | F | barred |
| 31x231 | 1st fret | G, root position | F | all fretted |
| x13233 | 1st fret | Bb, 1st inversion | G | barred |
| 353335 | 3rd fret | G, root position | A | barred |
| xx7066 | 6th fret | A, 9th in the bass | Bb | 1 open string |
| 687786 | 6th fret | Bb, 1st inversion | Bb | all fretted |
| x-10-8-10-10-x | 8th fret | G, root position | A | barred |
| x-12-12-12-11-13 | 11th fret | A, 9th in the bass | F | barred |
| x-x-12-14-11-13 | 11th fret | D, 2nd inversion | F | all fretted |
The same notes rebuilt from scratch give 13 drop 2, 8 drop 3, 14 rootless and 3 open string voicings, each on its own page.
Tensions. A shell of Gm9, 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 Gm9 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.
In which keys. Every note of Gm9 belongs to D minor (the iv, the subdominant), F major (the ii, the supertonic), G minor (the i, the tonic) and Bb major (the vi, the submediant).
Every note of Gm9 is in G dorian and G natural minor.
Change one note of Gm9 and you have Gm69 (the flat seventh becomes a sixth), Gm7 (drop the ninth), Gm11 (add the fourth), GmMaj9 (the flat seventh becomes a major seventh), Gmadd9 (drop the flat seventh) or G9 (the minor third becomes a major third).
Gm9 is a minor chord — root, minor third, fifth. Minor chords on every root.
On Gm9’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.