guitar chord
G♭m6
A minor triad with a major sixth added, which is why it is not simply a minor chord with a flat seventh.
Written the other way round it is F♯m6 — the same twelve keys on a piano, a different piece of notation.
Every fingering that fits a hand
20122x
moderate
2012xx
open · no 5
20424x
hard · no 5
244242
hard · barre
20124x
hard · no 5
What is true of it
G♭m6 is G♭, B♭♭, D♭ and E♭ — 1, b3, 5 and 6 counted from G♭.
B♭♭ is a double flat, and it has to be: every letter from G♭ upwards is used once, so the b3 cannot be written any other way.
These are also the notes of E♭m7♭5/G♭ and D♯m7♭5/G♭. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.
The easiest of the 5 fingerings below is 20122x: 4 fingers, held at the 1st fret.
1 of them use open strings, which is what makes a shape quiet to change to.
1 of the 5 need a barre.
1 string stays silent.
Where its notes are on the neck
The brass dots are G♭, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
G♭m6/B♭♭
x01222
G♭m6/D♭
x44645
G♭m6/E♭
xx1222
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.