guitar chord
A♯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 B♭m6 — the same twelve keys on a piano, a different piece of notation.
Every fingering that fits a hand
x13021
moderate
x13023
moderate
x1302x
open
64506x
hard
64306x
hard
What is true of it
A♯m6 is A♯, C♯, E♯ and F𝄪 — 1, b3, 5 and 6 counted from A♯.
F𝄪 is a double sharp, and it has to be: every letter from A♯ upwards is used once, so the 6 cannot be written any other way.
These are also the notes of Gm7♭5/A♯. 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 x13021: 4 fingers, held at the 1st fret.
1 of them use open strings, which is what makes a shape quiet to change to.
1 string stays silent.
Where its notes are on the neck
The brass dots are A♯, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
A♯m6/C♯
x45066
A♯m6/E♯
113023
A♯m6/F𝄪
31302x
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.