guitar chord
A♭add9
A major triad with a ninth added and no seventh — which is what tells it apart from a ninth chord.
Written the other way round it is G♯add9 — the same twelve keys on a piano, a different piece of notation.
Every fingering that fits a hand
4313xx
hard
xx6546
hard
4363xx
hard · no 5
xba8bx
hard
xbadbx
hard · no 5
What is true of it
A♭add9 is A♭, C, E♭ and B♭ — 1, 3, 5 and 9 counted from A♭.
On an instrument that cannot reach all 4, the 5 goes first, in that order.
The easiest of the 5 fingerings below is 4313xx: 4 fingers, held at the 1st fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
2 strings stay 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♭add9/C
8b88b8
A♭add9/E♭
xx1314
A♭add9/B♭
x1111x
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.