Chord inversions

A triad has three notes, so there are three ways to stack it. All three are the same chord.

The three positions

Take C major — C, E, G.

Root position — C on the bottom. C–E–G. First inversion — the third on the bottom. E–G–C. Second inversion — the fifth on the bottom. G–C–E.

The chord is named after its root, not its lowest note. E–G–C is C major in first inversion — it is not an E chord, because E is not functioning as the root.

How inversions are written

Slash chords are the common notation in lead sheets and pop music: the chord name, a slash, then the bass note.

• C — root position
• C/E — first inversion
• C/G — second inversion

Figured bass is the classical system, using numbers for the intervals above the bass: root position is 5/3 (usually unmarked), first inversion is 6/3 or just 6, second inversion is 6/4.

Why they exist

Not for variety's sake. Inversions solve a practical problem: voice leading.

Play C major then F major, both in root position, and the bass jumps a fourth and every note moves. Play C then F/C and the bass stays put while the upper notes shift by a step. The progression becomes smoother, and it is easier to play.

Three concrete uses:

Smoother bass lines. Inversions let the bass walk by step instead of leaping. C – G/B – Am gives a descending C–B–A bass under an ordinary progression.

Easier hands. On piano or guitar, an inversion often puts the notes where your hand already is.

Different weight. Root position is the most stable and final. First inversion is lighter and keeps things moving. Second inversion is the least stable — it wants to resolve, which is why the classical cadential 6/4 leads straight into the dominant.

Seventh chords

Add a fourth note and you get a third inversion as well, with the seventh in the bass. G7/F is a G7 with F on the bottom, and it pulls strongly downwards to the third of the next chord.