The A 6/9 chord is a five-note chord made up of A, C♯, E, F♯, and B. It is built from a root, major third, perfect fifth, major sixth, and major ninth.
Construction
A 6/9 = Root + Major 3rd + Perfect 5th + Major 6th + Major 2nd = A · C♯ · E · F♯ · B
| Note | Interval | Degree |
|---|---|---|
| A | Root | 1 |
| C♯ | Major 3rd | 3 |
| E | Perfect 5th | 5 |
| F♯ | Major 6th | 6 |
| B | Major 2nd | 2 |
Key Signature
A chord has no key signature of its own, but the A 6/9 is the tonic (I) chord of A Major, whose key signature has 3 sharps (F♯, C♯, G♯).
F♯C♯G♯
Order of sharps
Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.
F♯C♯G♯D♯A♯E♯B♯
Mnemonic: Father Charles Goes Down And Ends Battle
Chords in the Key of A Major
These are the triads built on each degree of the A major scale:
Same Notes, Other Names
The notes A – C♯ – E – F♯ – B aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:
A 6/9 — Frequently Asked Questions
What is the A 6/9 chord on piano?
The A 6/9 chord contains the notes A – C♯ – E – F♯ – B. On piano, play these notes together to sound the chord.
What notes are in the A 6/9 chord?
The A 6/9 chord (A6/9) contains 5 notes: A, C#, E, F#, B. Formula: R-M3-P5-M6-M9.
How is A6/9 used in music?
A6/9 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for A6/9?
A6/9 uses scale degrees 1-3-5-6-9, giving it its distinctive sound.