A#maj9 Chord on Guitar
A#maj9 = A# – D – F – A – C (Root, Major 3rd, Perfect 5th, Major 7th, Major 9th)
A#maj9 layers a ninth on top of a full major seventh chord, producing one of the lushest, most harmonically saturated sounds an A#-rooted barre chord can make at the sixth fret. Six strings can't hold every one of the chord's five tones at once, so the fifth is the note left out, freeing up a finger for the root, third, seventh, and ninth instead.
The full chord is A#, D, F, A, C — root, major third, fifth, major seventh, ninth — though the practical voicing keeps mainly root, third, seventh, and ninth. Unlike A#9, which includes a flat seventh and pulls hard toward Eb major as a dominant chord, A#maj9 keeps the major seventh and functions as a fully stable, resting tonic chord with no unresolved tension at all, just a wash of major color. That distinction — maj9 as a point of rest, plain 9 as a point of departure — is one of the more important things to internalize about extended chords generally.
Fingerings
Barre (6th fret)
How to Practice It
Play plain A#/Bb major, A#maj7, and A#maj9 in sequence to hear how each added tone thickens the color while staying fully at rest the whole time — none of these three chords pulls anywhere. Pay attention to how different that stillness feels compared to A#9's forward motion, since confusing the two is a common early mistake.
Common Progressions
- A#maj9 – Eb (I maj9 – IV, a lush stationary opening)
- Gm7 – A#maj9 – Eb (vi7 – I maj9 – IV, a smooth jazz-pop turnaround)
- A#maj9 – F/A# – A#maj9 (a static, ambient-leaning vamp on the tonic)
- Eb – A#maj9 – Gm7 (IV – I maj9 – vi7)
FAQ
- What's the difference between A#maj9 and A#9?
- A#maj9 stays fully stable and resolved because it keeps the major seventh alongside the added ninth; A#9 drops that major seventh for a flat one, and that's the single change that gives it a strong dominant pull toward Eb major.
- Is A#maj9 a chord that resolves somewhere?
- No — it's a stable tonic-family color chord that can sit comfortably as a resting point rather than pushing toward a resolution.
- Why does A#maj9 sound so lush?
- Stacking the major seventh and ninth on top of a plain triad fills in the harmonic space with closely related, consonant tones, producing a rich sound without introducing any actual dissonance.
- Does the guitar voicing of A#maj9 include every note?
- No — the fifth is dropped to keep the shape playable, leaving root, major third, major seventh, and ninth as the notes that carry the chord's identity.
- Is A#maj9 hard to finger at the sixth fret?
- It requires a comparable stretch to A#maj7 with one additional fretted note for the ninth, a reasonable step up once the plain major-seventh barre feels comfortable.
- Why might a songwriter choose A#maj9 over plain A#/Bb major for a verse?
- The added color creates a more atmospheric, less plainly strummed sound that suits slower, more textured arrangements.
- How can a player avoid confusing A#maj9 with A#9 by ear?
- The test is motion: A#9's flat seventh keeps pushing toward Eb major even with the ninth on top, while A#maj9 never asks to move anywhere at all — it's dressed up but at rest.
- Is there a way to play A#maj9 with fewer fretted notes?
- Some players simplify it further by dropping the third as well as the fifth, leaving essentially root, seventh, and ninth — a thinner but still recognizably lush voicing.
- Would A#maj9 work as an ending chord for a song?
- Very well — its complete lack of harmonic tension makes it a natural choice for a final, resolved-sounding chord, especially in slower or more atmospheric material.
- How does A#maj9 compare to a plain add9 chord built on the same root?
- A#add9 keeps the seventh out of the picture entirely, while A#maj9 keeps the major seventh in along with the ninth, giving maj9 a denser, more layered sound than the comparatively simple add9.
- Is A#maj9 ever used as an intro chord before a song's harmony is established?
- Yes — its lush, ambiguous-yet-stable color makes it a popular choice for atmospheric intros that ease a listener into a song's key without committing to a strong cadence right away.
- Does A#maj9 ever appear in acoustic singer-songwriter material?
- It does, especially in more introspective, fingerpicked songwriting where the extra harmonic detail rewards close listening in a way a simple strummed triad wouldn't.
A#maj9 on other instruments: A#maj9 on Piano. Related: how chords are built, chord finder.