Root position gave you one movable triad shape — the root sitting in the bass. Now meet the second shape: take the exact same three notes and put the 3rd on the bottom. That's a first-inversion triad, and it unlocks a whole new place on the neck for chords you already know.
Same triad, a different note on the bottom
A triad has three notes — root, 3rd, 5th. Inversion is just a question of which one is lowest. Put the root lowest and you have root position. Put the 3rd lowest and you have first inversion — same chord, same name, new voicing.
Here's C major with its 3rd (E) in the bass, on the top three strings:
Read the shape bottom-up: E, G, C. Still C, E, G — still a C major chord. Only the order changed, and that bass 3rd is the whole reason it's called first inversion.
Every role shifted one string
Line this up against root position and something clean happens: each string picks up the next chord tone. What used to be the root becomes the 3rd, the 3rd becomes the 5th, the 5th becomes the root an octave up.
| String | Root position | First inversion |
|---|---|---|
| 3 (G) — bass | Root | 3rd |
| 2 (B) | 3rd | 5th |
| 1 (e) | 5th | Root |
Because the roles moved, the switches you use to change the chord's quality move with them. In root position the major/minor switch lived on string 2 and the dim/aug switch on string 1. Here they slide over:
| Switch | Root position | First inversion |
|---|---|---|
| major/minor (the 3rd) | string 2 | string 3 |
| dim/aug (the 5th) | string 1 | string 2 |
| Root (fixed = chord name) | string 3 | string 1 |
That's the entire lesson. The rules for building each chord are identical to root position — a big 3rd is major, a small 3rd is minor, shrink or stretch the 5th for dim or aug. Only the string your finger moves on has changed.
The five triads in this shape
Every shape below keeps the root fixed on string 1, fret 8. The changed note (marked in each caption) is what turns C major into something else.
Major
Minor — lower the 3rd on string 3
Sus4 — push the 3rd up to the 4th (string 3)
Augmented — raise the 5th on string 2
Diminished — lower both the 3rd (string 3) and the 5th (string 2)
Fret summary
Written low-to-high, bass first: string 3 · string 2 · string 1.
| Chord | String 3 (3rd) | String 2 (5th) | String 1 (Root) | Notes (low → high) |
|---|---|---|---|---|
| Major | 9 (E) | 8 (G) | 8 (C) | E · G · C |
| minor | 8 (E♭) | 8 (G) | 8 (C) | E♭ · G · C |
| sus4 | 10 (F) | 8 (G) | 8 (C) | F · G · C |
| aug | 9 (E) | 9 (G♯) | 8 (C) | E · G♯ · C |
| dim | 8 (E♭) | 7 (G♭) | 8 (C) | E♭ · G♭ · C |
Bold cells are what changed from major. String 1 (the root) stays on fret 8 for all five — move that and you haven't changed the chord's quality, you've changed the key.
Don't confuse "first inversion" with "first chord." First inversion is about voicing — which note is in the bass (here, the 3rd). It has nothing to do with the I chord or the first degree of a key. A ii chord, a V chord, any chord can be played in first inversion.
Why 7th chords are awkward here
A 7th chord has four notes, but you only have three strings — so one note gets dropped. In root position that worked out nicely: you dropped the 5th (string 1) and the 7th slid comfortably into that spot.
First inversion doesn't cooperate. Here the 5th sits on string 2, and squeezing the 7th (B or B♭) into that slot lands it far up the neck:
- Cmaj7 → 9 · 12 · 8 (string 2's B is way up at fret 12)
- C7 → 9 · 11 · 8 (string 2's B♭ at fret 11)
That's an ugly stretch. It's a useful real-world lesson: not every chord type sits comfortably in every inversion or on every string set. For 7th chords, reach for root position on these strings — or a different string set entirely. The idea of a 7th (a note a step or half-step below the root) never changes; you're only choosing where on the neck to grab it.
It moves, like every shape
Slide the whole thing. Move the string-1 root to fret 10 (D) and the same fingering gives you the full family of D first-inversion chords. Because a key's chords now live in two places — the root-position spot and this first-inversion spot — chords stop being isolated islands. You can hop to whichever is closest, which is the foundation of smooth chord changes and voice leading.
Want to see this shape sitting alongside the other two inversions across the whole neck? The interactive triad fretboard lays all three out at once.
In one line: first inversion puts the 3rd in the bass — same triad, every role shifted one string, so the major/minor switch moves to string 3, the dim/aug switch to string 2, and the root to string 1. The building rules don't change, just the strings you move on. See where the root shape came from in movable triads.