Chord qualities: major, minor, diminished, augmented — Music Theory

The previous chapter encountered three chord qualities — major, minor, and diminished. There’s a fourth — augmented — that doesn’t appear in the major scale’s natural triads but completes the family.

All four follow the same construction principle: stack two thirds. The choice of which thirds — major or minor — produces all four qualities.

The four qualities as interval recipes

Quality	Symbol	Formula	Example (root = C)
Major	(none) or maj	root + M3 + P5	C – E – G
Minor	m	root + m3 + P5	C – E♭ – G
Diminished	dim or °	root + m3 + ♭5	C – E♭ – G♭
Augmented	aug or +	root + M3 + ♯5	C – E – G♯

These four recipes account for every triad in any key. Once you can derive the notes from the formula, you no longer need to memorize specific chords.

The 2×2 grid

The four qualities aren’t four random things. They’re a 2×2 matrix with two independent dimensions: the quality of the third, and the quality of the fifth.

	Perfect 5	Altered 5
Major 3	Major	Augmented (♯5)
Minor 3	Minor	Diminished (♭5)

Reading the grid:

Move the third between major and minor: switches between bright and dark.
Move the fifth between perfect and altered: switches between stable and unstable.

Two binary choices. Four possible outcomes. The whole family of triads.

Visualizing them on the strip

All four chords with root C Do :

C major

C minor

C diminished

C augmented

(The displayed sharps are enharmonic with the proper flat names — D♯ is E♭, G♭ is F♯. We’re using sharps here for the visual; theory-correct chord spellings prefer the flats.)

Notice the symmetry: each chord shifts one or two notes by a single half step, and the chord’s character changes dramatically. This is what makes chord progressions interesting — small changes in inner voices produce large emotional shifts.

When you’ll see each

Major and minor triads are the workhorses. The overwhelming majority of chords in any song you’ll play are major or minor.
Diminished triads appear naturally on the seventh degree of major keys and the second degree of natural minor. As standalone chords they’re rare; as diminished seventh chords (chapter 4) they’re common in rebetiko and laïkó as transitional chords.
Augmented triads are the rarest. They have an unsettled, suspenseful quality — used in Greek music sometimes for dramatic effect, more common in jazz and chromatic styles.

For Phase 1 of your bouzouki journey, focus on hearing the difference between major and minor. The other two will become important as you encounter more harmonically adventurous music.

Recap

The four triad qualities are major, minor, diminished, augmented — each defined by exact intervals from the root.
They form a 2×2 grid: the third’s quality is one axis, the fifth’s quality is the other.
Major and minor are by far the most common; diminished and augmented are used as color chords or transitions.
You don’t need to memorize all four formulas — memorize the major triad (root + M3 + P5) and the three single-note modifications that produce the others.