Circle of fifths
Keys, signatures, diatonic chords, functions and harmonic relationships.
C major (0)
Clockwise, each key is a fifth higher and adds a sharp.
C major
- Key signature
- No accidentals
- Relative
- Notes
- C · D · E · F · G · A · B
Diatonic chords
Top colour and letter: T = tonic (rest), PD = predominant (motion), D = dominant (tension that wants to resolve).
C on the fretboard
C (I) has tonic function: it sounds like rest, a point of arrival.
String 6, Open: E2 · 3 · Third
Cadences to listen to
- Authentic (V → I) · G → CThe most conclusive resolution: the dominant goes home.
- Plagal (IV → I) · F → CA soft resolution, the hymn amen.
- Half cadence (I → V) · C → GIt stops on the dominant: an open question.
- Deceptive (V → vi) · G → AmYou expect the tonic and get vi: a surprise that extends the phrase.
- ii – V – I · Dm → G → CThe core jazz progression: predominant, dominant, tonic.
Secondary dominants
A V7 of another degree of the key. It adds momentary tension toward that chord without changing key.
Modal interchange
Chords borrowed from the parallel key (same tonic, opposite mode) that add colour without modulating.
Closely related keys
The nearest keys share almost all their notes: they are the most natural modulation targets.