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Inversion does one thing: it puts a different chord tone in the lowest voice. The chord's name does not change, but the sound does.
root position: C lowest → C–E–G first inversion: E lowest → E–G–C second inversion: G lowest → G–C–E
All three contain exactly the same notes; only the bottom note differs. That one difference matters twice over:
1. the bass line becomes smooth — it need not keep leaping back to the root and can move by step; 2. the functional centre of gravity moves — the same chord over a different bass has different stability and different tendency.
Where figured bass comes from
In the continuo era (Baroque) composers wrote only the bass line and put figures under it to say which notes should sound above. The figures therefore encode inversion directly:
| Bass note | Figure | Meaning | Example (C chord) |
|---|---|---|---|
| root | 7 / none | root position | C in the bass |
| third | 6 | first inversion (a third and a sixth above) | E in the bass |
| fifth | 6-4 | second inversion (a sixth and a fourth) | G in the bass |
| seventh | 4-2 | third inversion of a seventh chord | B in the bass |
The other two inversions of a seventh chord are 6-5 (first) and 4-3 (second). The figures are still used in analysis today because they state directly which intervals sit above the bass, which "first inversion" does not.
Inversion is not just reordering
The commonest misreading treats it as a game of arrangement. In fact inversions carry definite functions:
| Inversion | Typical role |
|---|---|
| 6 (third in the bass) | lets the bass move by step, softens the sense of landing, keeps the motion flowing |
| 6-4 (fifth in the bass) | the least stable; common as a decoration inside a cadence or over a sustained bass |
| 4-2 (seventh in the bass) | the most tense, because the least stable note is placed in the most exposed voice |
In one line: inversion separates "what the chord is" from "what the bass is" — which is exactly what lets bass writing become a line in its own right.
How it differs from interval inversion
Interval inversion turns an interval upside down; chord inversion moves one chord tone down an octave to become the bass. Both change the up-down relation, but of different objects: one of the distance between two notes, one of the chord's bass position.
Diagram: one chord, three positions
Listen: inversions
One C major triad, three basses. Notice how the sense of landing weakens as the root leaves the bass.
Common misconceptions
- "Inverting turns the chord into a different chord." Neither the name nor the notes change; only the bass position does.
- "Inversion is just reordering notes." It carries function: smoothing the bass, softening the sense of landing, or creating tension inside a cadence.
- "Figured bass is an early form of chord chart." It states which intervals to place above the bass; it is a tool for composing and analysis, not a fingering chart.
- "The root is always the lowest note." Only in root position. In inversions the bass is the third, fifth or seventh — and the root is still the root.
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Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 转位 = 把和弦中除根音外的音放在最低声部；三和弦有两个转位、七和弦有三个，属和声学通则
- 低音位置标记法在数字低音（通奏低音）体系中的写法（6 / 6-4 / 7 / 6-5 / 4-3 / 4-2），为通行乐理表述
Used for fact-checking only; all prose is original.