To play A9 on the guitar, you need the notes A, C#, E, G, B. Its first guitar voicing is the movable voicing: low E string at fret 5 (ring finger); A string at fret 4 (middle finger); D string at fret 2 (index finger); G string open; B string open; high e string open. This guide covers the dominant 9th chord in full: what is in it, how to play it cleanly on the guitar, where it fits musically and how to practise it.
What notes are in the A9 chord?
The A9 chord is a dominant 9th chord, and its notes are fixed: A, C#, E, G, B. Every voicing on every instrument uses these same notes, in some order and in some octave — change one of them and you are playing a different chord. The table below lists each note with its interval from the root A, so you can see the structure of A9 at a glance. On the guitar, start with the first voicing above and listen for the notes A, C#, E, G, B in A9.
| Note | Interval |
|---|---|
| A | Root |
| C# | 3 |
| E | 5 |
| G | b7 |
| B | 9 |
The root is A, the note the chord is named after and the note your ear hears as home. Above it, the intervals in A9 are 3, 5, b7, 9. Once you know the intervals, you can build A9 from any root by counting the same semitone steps, which is how the chord works in every key. On the guitar, the notes appear in the order the fingering dictates, but the set of notes never changes.
A9 sounds open and sophisticated, a dominant chord with an extra colour note that never sounds crowded. Listen for that character when you play it — if A9 does not sound that way, one of the notes is probably wrong, and the table above is the place to check. On the guitar, the movable voicing of A9 puts those notes under your fingers in the order the fingering lists them.
Comparing A9 with its closest relatives helps to fix it in your ear. In short, 9th against dominant 7th: A9 is a dominant 7th chord with the 9th B added. The 7th (G) still does the work; the 9th just adds colour. Practise the two chords back to back and listen to the one note that changes — that single note is the difference between the two chords. On the guitar, the movable voicing of A9 puts those notes under your fingers in the order the fingering lists them.
How to play A9 on guitar
On the guitar, A9 has 3 voicings in the data below, and each one uses the same notes — A, C#, E, G, B — in a different place on the neck. There are 3 voicings listed for A9 on the guitar; learn the first, then add the others as you need them. Finger numbers below use 1 for the index finger, 2 for the middle finger, 3 for the ring finger and 4 for the little finger, and x means the string is not played.
Another way to play A9 is the movable voicing, in around fret 2: low E string at fret 5 (ring finger); A string at fret 4 (middle finger); D string at fret 2 (index finger); G string open; B string open; high e string open. The stretch is the challenge: the fretted notes span from fret 2 to fret 5, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in A9 — A, C#, E, G, B — sounds, with no buzz and no accidental open string.
Another way to play A9 is the barre chord, in around fret 2: low E string at fret 5 (middle finger); A string at fret 2 (index finger); D string at fret 2 (index finger); G string open; B string at fret 2 (index finger); high e string open. It barres across strings 2 to 3 at fret 2 with the index finger. The barre is the hard part: the index finger must press every string from 2 to 3 evenly at fret 2, so roll it slightly onto its bony side and keep it close to the fret wire. If the barre buzzes, move it a fraction closer to the fret and press from the arm, not the thumb alone. Strum or pluck it slowly first and check that every note in A9 — A, C#, E, G, B — sounds, with no buzz and no accidental open string.
Another way to play A9 is the movable voicing, in around fret 2: low E string at fret 5 (ring finger); A string at fret 2 (index finger); D string at fret 5 (little finger); G string open; B string at fret 2 (middle finger); high e string open. The stretch is the challenge: the fretted notes span from fret 2 to fret 5, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in A9 — A, C#, E, G, B — sounds, with no buzz and no accidental open string.
Choosing between the voicings of A9 is a musical decision, not a right-or-wrong one. The open or low-position voicing rings the most and suits strumming, while a barre or movable voicing lets you slide A9 up the neck to any key without changing the shape. When you change chords, pick the voicing of A9 that sits closest to the chord before it — shorter moves between shapes mean faster, cleaner changes. Practise the change into A9 from the chord that comes before it in your song, not the chord on its own, because the move is the skill. On the guitar, the movable voicing of A9 puts those notes under your fingers in the order the fingering lists them.
A short practice routine for A9 on the guitar: play the first voicing four times slowly, checking each note, then change to it from the chord a fourth above A and back, four times, at a slow tempo. Then play the second voicing the same way. If a note buzzes, stop and fix the finger placement rather than playing through the buzz — clean notes at a slow tempo become clean notes at full tempo, while buzzes practised fast become habits. Use the Guitar Chord Finder to see the diagram for A9 while you practise, and the Chord Finder to compare it with the same chord on other instruments.
Common mistakes
These are the mistakes that most often make A9 sound wrong on the guitar, and each one has a concrete fix. Work through them one at a time rather than trying to fix everything at once.
Crowding the voicing. Five notes are a lot. Drop the 5th (E) first — it adds the least — and keep the root, 3rd, 7th and 9th. On the guitar, start with the first voicing above and listen for the notes A, C#, E, G, B in A9.
Playing the 9th too low. B low down clashes with the root. Keep the 9th in a higher octave than the root and 3rd. On the guitar, the movable voicing voicing is the place to hear it in A9.
Using it as a tonic. A9 is a dominant chord. As a tonic it sounds restless; save it for the V. On the guitar, start with the first voicing above and listen for the notes A, C#, E, G, B in A9.
Barre collapsing on the high strings. In a barre voicing of A9, the high strings are the ones that buzz first, because the index finger presses hardest near the thumb. If the top notes of A9 sound dead, roll the barring finger slightly toward the fret and press from the arm, not from squeezing the neck. On the guitar, the movable voicing voicing is the place to hear it in A9.
Where A9 is used
A9 is not a diatonic triad in any major or minor key, because it is an extended or altered chord, but its base triad belongs to the key of D major, the key of E major, the key of A major. a turnaround chord: V9 to I is one of the most satisfying resolutions in popular music. As a dominant-type chord it also points toward D major, the key a perfect fourth above A, which is the tonic it most often resolves to. That is where A9 does its work: not as a home chord, but as a chord that creates movement and then resolves. On the guitar, start with the first voicing above and listen for the notes A, C#, E, G, B in A9.
Because A9 is an extended or altered chord, it appears in progressions as a colour or a dominant rather than as a diatonic staple. Try it in place of the plain A triad in a progression you already know, and listen to how the extra notes change the feel — that substitution is the usual way extended chords enter real music. The Chord Progression Builder lets you try A9 in a progression in any key and hear how it connects to the chords around it. On the guitar, the movable voicing voicing is the place to hear it in A9.
The same chord on other instruments is covered in A9 on piano, A9 on ukulele, A9 on bass, and the scales that fit over it are the A major scale and the A minor pentatonic scale. Learning A9 on the guitar and then checking it on another instrument is one of the best ways to fix the notes — A, C#, E, G, B — in your memory, because the notes stay the same while everything else changes.
Practising A9
A short worked example makes A9 concrete. Play the four-chord progression D – A – Bm – G in D major, the key A9 most often resolves toward: D – A – Bm – G. Play each chord for one bar at a slow tempo, and listen to how A9 sounds in that sequence — whether it feels like home, like a lift, or like a chord on its way somewhere else. Then play the same four chords in a different order, starting on A9 itself, and notice how its character changes when it opens the progression instead of sitting inside it. On the guitar, the movable voicing voicing is the place to hear it in A9.
For a second exercise, play A9 and then the chord a fourth above A, back and forth, four times each. That move — a chord and the chord a fourth above it — is the most common resolution in Western music, and it is the move A9 is built for when it acts as a dominant. Finish by playing A9 on its own, slowly, and naming each note out loud as you play it: A, C#, E, G, B. Naming the notes while you play them is what turns a shape into knowledge you can use in any key. Test yourself with the Practice Chord Quiz and keep time with the Metronome as the tempo rises. On the guitar, start with the first voicing above and listen for the notes A, C#, E, G, B in A9.
Frequently asked questions
What is the difference between A9 and Aadd9?
A9 includes the flattened 7th G; Aadd9 does not. That 7th makes A9 a dominant chord that wants to resolve, while the add9 is a settled tonic colour. On the guitar, the voicings above put that note under your fingers.
Which note can I drop from A9?
The 5th, E. The root, 3rd (C#), 7th (G) and 9th (B) define the chord; the 5th adds the least and is the first note to go in a tight voicing. On the guitar, the voicings above put that note under your fingers.
How do you play A9 on the guitar?
The first voicing is the movable voicing: frets 5–4–2–0–0–0, fingers 3–2–1–0–0–0, on the guitar. That voicing uses the notes A, C#, E, G, B, and it is the one to learn first. The page above lists more voicings for A9, so you can choose the shape nearest the chords around it.
Is A9 hard to play on the guitar?
It depends on the voicing. The first voicing of A9 on the guitar is the easiest starting point, and the movable voicings further up the neck are harder because they need a barre or a wider stretch. Practise the first voicing cleanly at a slow tempo before you try the others, and the harder shapes will come more easily.
What is the easiest voicing of A9 on the guitar?
The movable voicing is the easiest voicing listed for A9 on the guitar: frets 5–4–2–0–0–0, fingers 3–2–1–0–0–0. Learn that shape first, get every note ringing cleanly, and only then move on to the alternative voicings further up the neck.