Chord inversions: same chord, different bass note

Root position — the root is lowest: C–E–G. The most stable, and the default when a chord symbol appears alone.

First inversion — the third is lowest: E–G–C. Lighter and less settled, useful in the middle of a phrase rather than at the end.

Second inversion — the fifth is lowest: G–C–E. The least stable of the three, traditionally treated as a passing sound or as preparation for a cadence.

A seventh chord has four notes and therefore a third inversion, with the seventh in the bass. In figured-bass shorthand these are written 6, 6/4 and 4/2, and in Roman numeral analysis they appear as I6, I64 and V42.

In chord charts an inversion is written as a slash chord: C/E means a C chord with E in the bass. The letter before the slash is the chord, the letter after it is the bass note.

Not every slash chord is an inversion. C/E, C/G and C/Bb use notes of the chord; C/D does not, and that is a different device — a chord over a bass note that does not belong to it, common in pop for its unresolved sound.

For a guitarist reading a chart, the practical reading is simple: play the chord named first, get the note named second into the bass, and let anything else fall where it fits.

Smooth bass lines. C–G–Am–F moves the bass by leaps. Written C–G/B–Am–F, the bass walks down C–B–A–F, and the progression stops sounding like four separate chords.

Less hand movement. On piano, playing C in root position and F in second inversion keeps the hand in one place instead of jumping. Most keyboard voicing is this consideration applied repeatedly.

Weight. Root position is heavy and final; inversions are lighter. A phrase that ends in first inversion sounds like it wants to continue, which is exactly what you want in the middle of a verse.

Open chords are often inverted without anyone noticing: a standard open C has C in the bass, but the common D/F# shape and the folk favourite G/B are inversions used because they smooth the bass line.

Barre shapes make the logic visible. The E-shape barre puts the root in the bass; the A-shape puts the root in the bass too; moving a triad onto the top three strings and rearranging the notes gives inversions that sit high and thin, useful when a bass player already covers the low end.

The most useful three to learn first are D/F#, G/B and C/E — together they cover most of the descending bass lines in folk and pop.

Play C–E–G with the right hand, then move the lowest note up an octave: E–G–C, first inversion. Move the lowest again: G–C–E, second inversion. Moving the top note down an octave does the same thing in reverse.

Practise a progression by choosing, for each chord, whichever inversion is closest to the previous one. The hand stops jumping almost immediately, and that habit is most of what separates a comfortable accompaniment from an awkward one.

In two hands the usual division is bass note in the left, the rest in the right — which means the left hand alone decides the inversion.

Inversions are the tool; voice leading is the reason to use them. Which inversions are available depends on the chords of the key, and moving the whole set to another key is transposition.