The B9 chord on guitar, from the funk shape to the full barre

B9 is B7 with one more note on top, C#, and that note changes the mood more than the job. The chord still leads to E, but it does it with a soul and funk sheen instead of a folk twang. The good news: the most used B9 shape sits in the first two frets and needs no barre. Learn it on four strings, then fill it out.

B9 chord: notes and shapes at a glance

• Name: B dominant ninth
• Symbol: B9
• Notes: B, D#, F#, A, C#

Each shape below is written from the thickest string to the thinnest: a number is the fret, 0 an open string, x a string you do not play. New to this? See how to read chord diagrams.

Read each diagram from the thickest string on the left to the thinnest on the right. A cross means the string is not played, a circle means it rings open.

How to play B9, from four strings to five

1. The funk shape: x2122x

Second finger on the A string at fret 2 (B, the root). First finger on the D string at fret 1 (D#, the third). Third finger on the G string at fret 2 (A, the seventh). Fourth finger on the B string at fret 2 (C#, the ninth). Leave both E strings silent: the tip of the second finger touches the low E, and the underside of the fourth finger rests on the high E.

There is no F# in this shape, and you will not miss it. Guitarists drop the fifth of a ninth chord all the time: it adds weight, not color.

2. Five strings: x21222

Keep the first two fingers where they are and lay the third finger flat across the G, B and high E strings at fret 2. The high E now gives you F#, and all five notes of B9 ring. The flat third finger has to bend backward a little at the first joint so it does not touch the D string.

3. The barre: 797877 plus one

Play the B7 barre at the seventh fret, then put the fourth finger on the high E at fret 9. That note is C#, so B7 becomes B9: 797879. The low E string gives you B in the bass, which suits a slower song.

B9, B7 and Badd9 side by side

Three chords with similar names and different jobs. What separates them is whether the A, the seventh, is there and whether C#, the ninth, is there.

From x21202 to x2122x, only one finger moves: the fourth finger slides from the high E to the B string, still at fret 2. The open B of B7 becomes C#. Switch between them slowly and you will hear the ninth arrive.

Where B9 fits

B9 does the same job as B7: it is the dominant of E, the chord that comes just before the song lands on E. Use it wherever B7 is written and the style is blues, funk, soul or jazz. In a twelve bar blues in E, players often turn every chord into a ninth: E9, A9 and B9.

The funk shape loves a short, muted strum. Play x2122x on the beat, release the pressure right after so the strings go dead, and you have the choppy sound of a funk rhythm part. Strum the same shape and let it ring, and it turns soft and jazzy.

You may also see a wider voicing, x24645: B, F#, C#, D# and A, all five notes, with the root on the A string at fret 2 and the ninth on the G string at fret 6. It is correct, but the stretch from fret 2 to fret 6 is hard and the shapes above give you the same chord with far less effort.