A9 is an A7 with one more note, B, the ninth. It does the same job as A7, with more warmth: in a blues in A it can replace A7 on the home chord, and in funk the four note version at the twelfth fret is one of the shapes rhythm players live on. The open version keeps the A string ringing as its root, which gives it a weight the funk shape does not have.
A9 chord: notes and shapes at a glance
- Name: A dominant ninth
- Symbol: A9
- Notes: A, C#, E, G, B
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.
| Shape | Frets, low E to high E | Notes, low to high | What it is for |
|---|---|---|---|
| A9, open A string | x02423 | A E B C# G | All five notes, with the open A as the root. Asks for a small stretch from fret 2 to fret 4. |
| A9, top four strings | xx2423 | E B C# G without A | The same shape without the root. Use it when a bass player or another guitar holds the A. |
| A9, fifth fret barre | 575657 | A E G C# E B | The A7 barre with the fourth finger adding B on the high E. Full and complete on all six strings. |
| A9, funk shape | x 12 11 12 12 x | A C# G B without E | Second finger on A at 12, first on D at 11, third and fourth on G and B at 12. No fifth, nothing open: built for muted sixteenths. |
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.
A9 on the neck: every A, C#, E, G, B
Standard tuning, frets 0 to 12. The highlighted notes are the notes of A9: any shape you build from them, anywhere on the neck, is still A9.
How to play A9 with the open A string
The shape x02423 has five notes, one per string from the A string up. Put the fingers down in this order, so the stretch comes last.
| String | Fret | Note | Role | Finger |
|---|---|---|---|---|
| 5 (A) | 0 | A | Root | open |
| 4 (D) | 2 | E | Fifth | 1 |
| 3 (G) | 4 | B | Ninth | 3 |
| 2 (B) | 2 | C# | Major third | 2 |
| 1 (high E) | 3 | G | Minor seventh | 4 |
The first and second fingers are both at fret 2, on the D and B strings. Some players lay the first finger flat across both and free the second finger; try both and keep the one that lets the G string ring. That G string, at fret 4 under the third finger, is the ninth: if it is muffled, you are playing A7.
The funk shape at the twelfth fret
x 12 11 12 12 x is exactly the E9 funk shape, x7677x, moved up five frets. Second finger on the A string at 12 for the root, first finger on the D string at 11 for C#, third and fourth fingers on the G and B strings at 12 for G and B. There is no fifth, and nothing rings open, so the chord stops the moment you relax the fretting hand.
That is the point. Funk rhythm is sixteenth notes with the strumming hand always moving and many strokes muted: the fretting hand lifts its pressure between hits without leaving the strings. Mute the low E with the tip of the second finger and the high E with the underside of the first, and you can strum across all six strings. Two frets down, the same shape is D9.
A9 in a blues in A
A twelve bar blues in A uses three chords: A, D and E, usually all played as seventh chords. Swap them for ninths and the whole progression gets smoother, closer to Chicago blues and soul than to the campfire.
With the funk shape, the D9 and E9 sit at frets 5 and 7 and the A9 at fret 12. If you would rather stay low, play A9 as the fifth fret barre: the D9 is then right next to it.
A9, A7 and Aadd9: what each adds
| Chord | Notes | Sound |
|---|---|---|
| A7 | A, C#, E, G | Dominant, bluesy, pulls to D |
| A9 | A, C#, E, G, B | Dominant too, warmer and smoother |
| Aadd9 | A, C#, E, B | Major and bright, no pull at all |
The ninth is the same note in A9 and Aadd9. What decides the character is the G: with it, the chord is a dominant; without it, it is a decorated A major.
Frequently asked questions
How do you play A9 on guitar?
What notes are in an A9 chord?
What is the difference between A7 and A9?
What is the difference between A9 and Aadd9?
How can I play A9 without the stretch?
Who made this
Guitar Social Club is the work of Yohann Abbou, a guitar teacher in Paris who teaches adults. Every shape on this page is written string by string and checked against standard tuning, and the diagrams are drawn from those same fret numbers. The rest of our free guitar tools, including the chord finder, work the same way.
More about Yohann on his page, and about why Guitar Social Club exists.