Chord & FretHarmonic field: the chords of every key
The harmonic field is the set of chords a scale produces when you stack thirds on each of its degrees. Understanding a key is not memorizing chord lists: it is seeing how degrees, chords and functions connect — and where they fall on the fretboard.
In C major, the collection C–D–E–F–G–A–B yields a triad (a three-note chord) and a seventh chord (the same chord plus its seventh, a fourth note) on every degree; the qualities (major, minor, half-diminished) follow from the real intervals between the collection’s notes. The most practical functional reading gives these chords three roles: tonic (I, vi and sometimes iii) stabilizes; subdominant (ii and IV) prepares; dominant (V and vii°) builds the tension that asks to resolve. These are tendencies of use, not absolute rules.
Tonic chords stabilize and rest; subdominant chords prepare motion; dominant chords build the tension that asks for resolution.
Example: C major
| Degree | Triad | Seventh | Function |
|---|---|---|---|
| I | C | Cmaj7Cmaj7Cmaj7Cmaj7 | tonic |
| ii | Dm | Dm7Dm7Dm7Dm7 | subdominant |
| iii | Em | Em7Em7Em7Em7 | tonic |
| IV | F | Fmaj7Fmaj7Fmaj7Fmaj7 | subdominant |
| V | G | G7G7G7G7 | dominant |
| vi | Am | Am7Am7Am7Am7 | tonic |
| vii° | B° | Bm7b5 | dominant |
Example: A minor
| Degree | Triad | Seventh | Function |
|---|---|---|---|
| i | Am | Am7Am7Am7Am7 | tonic |
| ii° | B° | Bm7b5 | subdominant |
| III | C | Cmaj7Cmaj7Cmaj7Cmaj7 | tonic |
| iv | Dm | Dm7Dm7Dm7Dm7 | subdominant |
| v | Em | Em7Em7Em7Em7 | dominant |
| VI | F | Fmaj7Fmaj7Fmaj7Fmaj7 | tonic |
| VII | G | G7G7G7G7 | dominant |
This is the natural-minor field. In practice the v often becomes V (major) or V7 — borrowed from the harmonic minor — to create the leading tone that pulls back to the tonic.
All 24 keys, around the circle of fifths
Major keys
Minor keys
In Chord & Fret, the Circle of Fifths screen shows any key’s harmonic field with audio and fretboard positions — triads, sevenths and the secondary dominants. Open in Chord & Fret →
Frequently asked questions
What is the harmonic field of a key?
It is the set of chords built by stacking diatonic thirds on each degree of the key’s scale. In C major: C, Dm, Em, F, G, Am and B° (triads) — or Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7(b5) (sevenths).
How do the major and minor fields differ?
The major field comes from the major scale; the minor one from the natural minor. In practice a minor key mixes materials: the v often becomes V or V7 (from the harmonic minor) to create the leading tone — the note a half step below the tonic that pulls back home.
What do tonic, subdominant and dominant mean?
They are the three practical functions: tonic chords stabilize or rest; subdominant chords prepare motion; dominant chords hold the tension that tends to resolve to the tonic.
Do I need to memorize all 24 fields?
No. Master C major and A minor as your reference axis — degrees and functions are the same in every key; only the notes change. Transposing beats memorizing.