Chords, Inversions & Figured Symbols
How a triad's three notes can be reordered into first and second inversion, and the figured-bass shorthand composers use to show which one.
Explainer
A triad in root position has its root at the bottom. First inversion puts the 3rd at the bottom instead; second inversion puts the 5th at the bottom.
Figured bass is a shorthand written below (or beside) a Roman numeral, showing which inversion is meant: root position needs no figure; first inversion is marked 6; second inversion is marked 6/4.
In C major, the tonic triad (I) is C-E-G in root position, E-G-C in first inversion (I⁶), and G-C-E in second inversion (I⁶₄).
Inversions let a bass line move more smoothly between chords, stepping or leaping only a little rather than always jumping to each chord's root.
Worked examples
Root position: C-E-G
The root (C) sits at the bottom — no figure needed.
First inversion: E-G-C (I⁶)
The 3rd (E) sits at the bottom — figured 6.
Second inversion: G-C-E (I⁶₄)
The 5th (G) sits at the bottom — figured 6/4.