Chord progression
I–V–vi–IV chord progression
Four chords that loop forever: home, tension, a minor colour and a lift back. Probably the most used progression of the last fifty years.
I–V–vi–IV in all 12 keys
Every row is the same progression moved to another key. Tap a chord for its shapes, or play a row to hear it.
Why I–V–vi–IV works
The progression starts at home (I), jumps to the chord of greatest tension (V), then, instead of resolving, slips to the minor vi, the relative minor of the key. That surprise gives it its bittersweet colour. IV then lifts the music away again, and because IV leads so naturally back to I, the loop restarts without a seam.
Every chord shares at least one note with the next, so the hand moves very little on the piano and the shapes are all open chords on guitar in keys like C, G and D. The bass line falls and rises in steps, which makes the loop easy to sing over.
How to practise it
Strum four even beats per chord, then try two bars per chord for a ballad feel. On piano, keep the right hand close: play the inversions that move by the smallest steps, as the play button does.
Use the metronome: start around 70–80 BPM with two or four beats per chord, and change chords exactly on the first beat. When the changes are clean, raise the tempo in small steps and try the same pattern in two or three other keys from the table.
Choosing a key
Which key to use? Whatever suits the singer or the instrument. Guitarists usually prefer G, D, A, E and C for I–V–vi–IV, because the chords are open shapes there; pianists often start in C. The table above has every key, and each chord links to its diagrams, so you can switch keys without working anything out.
Variations
Start the same loop on vi to get vi–IV–I–V, a darker version of the same four chords. Replace V with a sus4 that resolves, or play IV as IVmaj7 for a softer colour.