A cadence is a typical chord progression — a recurring pattern that shows up in countless songs. Instead of writing it out with fixed chord names (C, F, G…), you use scale degrees: roman numerals that show how far a chord is from the key’s root.
Why degrees instead of chord names?
I–IV–V means: the root, the fourth degree, the fifth degree. In the key of C, that’s C–F–G. In the key of G, it’s the exact same cadence, just written as G–C–D. The relationship between the chords stays the same — only the key changes. That’s why you can learn a cadence once and transpose it into any key.
A few well-known cadences
- I–IV–V — the foundation of the blues.
- I–V–vi–IV — the “pop cadence”, found in hundreds of songs.
- ii–V–I — the jazz cadence, the standard pattern for jazz harmony.
- i–VI–III–VII — a typical minor-key progression in rock/pop.
Lowercase roman numerals (ii, vi) stand for minor chords, uppercase (I, IV, V) for major — that follows automatically from the scale.