What notes are in the B9 chord?

B9 is made of B, D#, A and C#: the root, major 3rd, minor 7th and major 2nd above B.

What is the easiest way to play B9?

Play 747447 (low E to high E): barre fret 4 from the A to the B string.

B9 chord on guitar

B9 is a dominant ninth chord: funky and full. It is built from B, D#, A and C# (formula 1 3 ♭7 9). Dominant ninths are the classic funk and soul rhythm chord, and a richer swap for a plain seventh. The easiest way to play it in standard tuning is 747447.

7 4 7 4 4 7

x x 9 8 10 9

x 14 11 14 12 11

B9 fingerings (low E to high E)

Barre at fret 4: 747447. Barre fret 4 from the A to the B string.
Fret 8: x-x-9-8-10-9. Mute the low E and A strings.
Barre at fret 11: x-14-11-14-12-11. Mute the low E string, barre fret 11 from the D to the high E string.

Questions

What notes are in the B9 chord?: B9 is made of B, D#, A and C#: the root, major 3rd, minor 7th and major 2nd above B.
What is the easiest way to play B9?: Play 747447 (low E to high E): barre fret 4 from the A to the B string.

Also try: B Major · B Minor · B7 · Bmaj7 · Chord Charts