A chord is three or more notes played together. A progression is a sequence of chords. Most songs use a handful of chords from one key in an order that creates tension and release - and once you can build those chords yourself, you can write progressions in any key.
Building triads
A triad stacks two intervals of a third on a root note.
- Major triad - root, major third, perfect fifth. C-E-G. Bright, stable.
- Minor triad - root, minor third, perfect fifth. A-C-E. Darker, softer.
- Diminished triad - root, minor third, diminished fifth. B-D-F. Tense, unstable.
- Augmented triad - root, major third, augmented fifth. C-E-G#. Unsettled, dreamlike.
The quickest method on a keyboard: play a root, skip a note of the scale, play the next, skip, play the next. That stacks thirds automatically.
Deriving the chords of a key
Build a triad on every note of a major scale, using only notes from that scale, and you get seven chords with a fixed pattern of qualities:
- I - major
- ii - minor
- iii - minor
- IV - major
- V - major
- vi - minor
- vii° - diminished
In C major: C, Dm, Em, F, G, Am, B°. In G major: G, Am, Bm, C, D, Em, F#°. The pattern is identical in every major key.
In a natural minor key the pattern shifts: i, ii°, III, iv, v, VI, VII. In A minor: Am, B°, C, Dm, Em, F, G - the same chords as C major, starting from a different place.
Roman numerals
Roman numerals name chords by their position in the key rather than their letter, so a progression can be described in any key at once. Upper case means major (I, IV, V); lower case means minor (ii, iii, vi); a small circle means diminished (vii°).
"I-V-vi-IV" is C-G-Am-F in C, G-D-Em-C in G, and D-A-Bm-G in D. Learn progressions as numerals and you can play them in any key.
Common progressions
- I-IV-V - C-F-G. The foundation of blues, rock and roll, country and folk.
- ii-V-I - Dm-G-C. The backbone of jazz, and the strongest way to arrive home.
- I-ii - C-Dm. A gentle two-chord vamp.
- I-V-vi-IV - C-G-Am-F. Probably the most-used pop progression of the last forty years.
- vi-IV-I-V - Am-F-C-G. The same four chords starting on the minor - instantly more wistful.
- i-iv-v - Am-Dm-Em. The minor-key equivalent of I-IV-V.
- The Andalusian cadence - Am-G-F-E (i-VII-VI-V in minor). A stepwise descent from flamenco that runs through rock and pop. Using E major rather than E minor at the end (borrowed from harmonic minor) gives it a much stronger pull back to Am. A version ending on Em is softer.
Progressions and emotion
Chords carry feeling, and particular moves have recognisable characters:
- I-IV-V (e.g. G-C-D) - upbeat, anthemic, even manic. Pop and rock at its most direct.
- I-iv - a major chord to the minor four (e.g. E to Am, borrowing the minor iv from the parallel minor). Drama, wrenching emotion, moodiness.
- I-ii (e.g. A to Bm) - mellow, emotionally neutral, resigned.
- i-iii - two minor chords that do not normally sit together in the same key. Darkness, mystery, suspense, foreboding.
- A descending line inside a chord - C, Cmaj7, C7, F: the top note falls by semitones while the chord stays, pulling towards IV.
- Major seventh to minor (e.g. Bbmaj7 to Am/C) - lush, bittersweet, the sound of neo-soul and late-night pop.
These are tendencies, not rules. Tempo, rhythm, sound and lyric change everything. But knowing them lets you choose a progression for the feeling you are after.
Writing better progressions
- Change chords where it matters. One chord per bar is common; two per bar adds energy; a chord that lasts two bars gives space.
- Resolve at the end of the phrase. End sections on I for finality, on V to make the listener want more.
- Vary the rhythm of the chords. The same progression played as sustained pads, rhythmic stabs or broken arpeggios sounds like three different songs.
- Mind the bass. Putting a different note in the bass - an inversion - can turn an ordinary progression into something special.
Do this now
- Build all seven diatonic chords in C major and in G major, and label them with Roman numerals.
- Play I-V-vi-IV and vi-IV-I-V in three different keys.
- Program the Andalusian cadence in A minor twice - once ending on Em, once on E major - and compare them.
- Write an eight-bar progression for your C major project that ends on V and loops back to I.