A Major Chord (A)

1Composition: what it contains

A – C♯ – E

Symbol

A

Also written

A, AM, Amaj, AΔ

Formula

1 3 5

2Appearance: diagrams and sound

On the guitar

On the ukulele

On the piano

On the staff

On bass and as an arpeggio

3Indications: what it is used for

The I, IV and V chords of every major key are major triads, so it is the backbone of pop, rock, folk, country, gospel and classical harmony. In minor keys it appears as III, VI and VII, and as the major V chord borrowed from harmonic minor. Progressions like I–IV–V, I–V–vi–IV and I–♭VII–IV rely on it. It can be replaced by a major seventh, sixth, add9 or 6/9 chord for a richer colour, or by its relative minor (vi for I) in reharmonisation.

4Dosage: how to practise it

On guitar, learn the open shapes first, then the barre shapes with the root on the sixth and fifth strings, and finally the small triad shapes on the top three strings in all three inversions. On piano, play root position, first and second inversion with each hand at 60 BPM, then move through I–IV–V with the smoothest voice leading. On bass, arpeggiate 1-3-5-8 and back. Spend five minutes daily switching between two chords on every beat, raising the tempo by 5 BPM when the change is clean.

5Warnings and common mistakes

Do not confuse it with the minor triad: only the third changes, and that one half step changes everything. Doubling the third in thick voicings can sound heavy; double the root or fifth instead. On guitar, check that the third is actually present in power-chord-like shapes. A chord symbol with just the letter means major: an 'M' or 'maj' written alone is the same chord, but 'M7' or 'maj7' adds a seventh.

6Interactions with chords, scales and keys

Inversions

• Inversion 1 · A/C♯ · C♯ – E – A Play
• Inversion 2 · A/E · E – A – C♯ Play

Scales to play over A

• A Major Scale
• A Lydian Mode
• A Mixolydian Mode
• A Major Pentatonic Scale
• A Major Blues Scale
• A Half-Whole Diminished Scale
• A Phrygian Dominant Scale
• A Lydian Dominant Scale
• A Double Harmonic Major Scale
• A Bebop Dominant Scale

Where it appears (keys and Roman numerals)

• V – Key of D Major
• I – Key of A Major
• IV – Key of E Major
• VII – Key of B Minor
• III – Key of F sharp Minor
• VI – Key of C sharp Minor
• V – Key of D Minor

7Other presentations available

The same chord from every note

C C♯ D E♭ E F F♯ G A♭ B♭ B

Other chords on A

Am Adim Aaug Asus2 Asus4 A5 A6 Am6 A7 Amaj7 Am7 Am7♭5 Adim7 Am(maj7) A7sus4 Aadd9 Am(add9) A6/9 A9 Amaj9 Am9 A11 Am11 A13 A7♭9 A7♯9 A7♯5 A7♭5