Triads and Inversions

The goal of this module: stop memorizing chord shapes and start constructing chords from intervals. Then you can voice any chord anywhere on the guitar or the piano.

The idea

A triad is a root, a 3rd and a 5th: two 3rds stacked on top of each other. There are four types.

Triad	Formula	Stacked 3rds	Sound
Major	1 3 5	major 3rd + minor 3rd	Bright, resolved
Minor	1 ♭3 5	minor 3rd + major 3rd	Dark, resolved
Diminished	1 ♭3 ♭5	minor 3rd + minor 3rd	Tense, unstable
Augmented	1 3 ♯5	major 3rd + major 3rd	Dreamlike, unresolved

Build any of them on any root. Switch the inversion and listen to how the same three notes change color:

Inversions use the same notes with a different one in the bass:

Position	Bass note	C major	Written
Root position	Root	C E G	C
1st inversion	3rd	E G C	C/E
2nd inversion	5th	G C E	C/G

Inversions matter because they create bass lines. C – C/E – F gives the bass a walk up C, E, F instead of a jump. The piano part of “Let It Be” does the mirror image on the way down: F – C/E – Dm – C. Slash chords are the songwriter’s tool for smooth, purposeful bass movement under simple harmony.

On your instrument

Guitar. Learn triads on three string sets: 1-2-3, 2-3-4 and 3-4-5. For each set, learn major and minor in all three inversions as small movable shapes. These little triads are the rhythm-guitar vocabulary of funk, pop and indie, and the twin-lead vocabulary of metal. Big open chords are for strumming. Small triads are for arranging.

C major on strings 3-2-1, in three places on the neck:

     root pos.   1st inv.   2nd inv.
e|-----3-----------8-----------12----|
B|-----5-----------8-----------13----|
G|-----5-----------9-----------12----|
       C E G       E G C       G C E

To make any of them minor, lower the 3rd (the E) by one fret.

Piano. Play C, C/E and C/G up and down with the right hand. Then take Am – F – C – G and connect the chords with the smallest possible hand movement: Am (A C E), F (A C F, one finger moves), C (G C E), G (G B D).

Worked example

I – V – vi – IV in C on the top three strings, staying inside a three-fret area:

       C       G       Am      F
e|-----3-------3-------5-------5-----|
B|-----5-------3-------5-------6-----|
G|-----5-------4-------5-------5-----|

No chord is more than two frets from the one before. Am and F share two notes, so only one finger moves. Compare that with jumping between open C, G, Am and F cowboy chords: same harmony, completely different level of polish.

Now a bass line made from inversions. Play G – D/F♯ – Em – C and listen to the lowest notes: G, F♯, E, C. The descending bass is the hook, and the chords on top are ordinary.

Exercises

1. On paper, spell major, minor, diminished and augmented triads on all 12 roots. Fifteen minutes, once.
2. Guitar: play C major in all three inversions on strings 1-2-3. From each one, find the nearest F major shape, then the nearest G. You are now voice-leading on guitar.
3. Rewrite C – G – Am – F with slash chords so that the bass walks down by step. One answer: C – G/B – Am – Am/G – F, with the bass going C, B, A, G, F.
4. Take any four-chord song you know and play it with three-string triads instead of full chords. Record both versions.

Common mistakes

• Always playing all six strings. A triad has three notes. Doubling them five times makes the part louder, not better.
• Ignoring the lowest note. Whatever note is lowest is what the listener hears as the bass. If you play C/G by accident, the chord feels less stable.

Check yourself