The chords
Every chord links to its full reference page — notes, keyboard diagram, audio, fingering, and inversions.
Which key is it in?
A progression's key is the one whose scale contains all of its chords, and the Roman numerals below are each chord's job in that key. When several keys qualify, the ear usually decides by where the music comes to rest.
| Key | Roman numerals | Named pattern |
|---|---|---|
| D major | I – vi – ii – V | The "Heart and Soul" loop |
| B minor | ♭III – i – iv – ♭VII | Not a named pattern |
| C♭ minor | ♭III – i – iv – ♭VII | Not a named pattern |
Why The "Heart and Soul" loop works
A turnaround loop (also the A-section of Rhythm Changes): home, relative minor, then the ii–V that cycles you straight back to the top.
The full The "Heart and Soul" loop reference → covers variations, songs built on it, and the pattern in every key.