guitar chord
B♭9
A dominant seventh carrying a ninth on top.
Written the other way round it is A♯9 — the same twelve keys on a piano, a different piece of notation.
Every fingering that fits a hand
x10111
moderate
x1011x
open · no 5
x10114
hard · no 5
x10314
hard · no 5
686768
hard · barre
What is true of it
B♭9 is B♭, D, F, A♭ and C — 1, 3, 5, b7 and 9 counted from B♭.
On an instrument that cannot reach all 5, the 5 and 1 go first, in that order.
The easiest of the 5 fingerings below is x10111: 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 B♭, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
B♭9/D
xx0111
B♭9/F
11011x
B♭9/A♭
43033x
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.