Chords from outside the key
Most chords of a song are the key’s own, built from its seven notes. The ones that are not are often the ones you remember: the minor iv that darkens the last line of a ballad, the D7 that leads into the bridge of a standard. Harmony has names for why they are there, and the chord sheet writes them under the chords, each in a colour:
| Colour | Kind | Written |
|---|---|---|
| blue | a chord borrowed from the minor key on the same tonic | iv · borrowed |
| yellow | a secondary dominant, the dominant of another chord | V7/vi |
| pink | the Neapolitan chord | N⁶ |
| orange | a pivot chord into a new key | vi = ii · pivot |
The key’s own chords stay grey. Point at a numeral and its tooltip explains what the chord does and which of its notes are from outside the key.
To try it, make a new song, open the chord sheet and type these sixteen bars: C, Fm, Ab, G7, C, E7, Am, D7/F#, G, C, Db/F, G, C, Am, D7, G. Then right-click bar 15 in the playlist’s bar numbers and choose G under Key from bar 15. The chord sheet colours the numerals as in the picture.
Borrowed chords
C major and C minor share their tonic, C, and their dominant, G: they are parallel keys. Music in a major key often takes a chord from its parallel minor for a moment without leaving the key. This is borrowing, or modal mixture:
| Chord | In C major | Its notes | From C minor |
|---|---|---|---|
| Fm | iv | F A♭ C | A♭ |
| A♭ | ♭VI | A♭ C E♭ | A♭ and E♭ |
| B♭ | ♭VII | B♭ D F | B♭ |
| E♭ | ♭III | E♭ G B♭ | E♭ and B♭ |
| D° | ii° | D F A♭ | A♭ |
| Bdim7 | vii°7 | B D F A♭ | A♭ |
The ♭ in ♭VI says the chord is built on a lowered sixth note: A♭ where C major has A. A borrowed chord darkens the major key without leaving it. iv to I, Fm to C, is the minor plagal cadence: the A♭ falls to G. ♭VII to I, B♭ to C, is the rock cadence. The Minor plagal demo is built on the first.
Borrowing goes the other way too. A piece in A minor that ends on A major borrows its last chord from A major: that bright ending is the Picardy third, and has a demo of its own. The tooltip names it when a minor piece ends that way.
Secondary dominants
In C major, G7 is the dominant: its B is a semitone below C and pulls up to it, which makes C sound like home. Any major or minor chord of the key can get a dominant of its own. D7 is the dominant of G: its F♯ is a semitone below G and pulls up to it. F♯ is not in C major, so for a moment G sounds like a home of its own. This is a tonicization, and D7 in C major is written V7/V, “five seven of five”.
| Chord | Its dominant | Written | The note from outside |
|---|---|---|---|
| Dm (ii) | A7 | V7/ii | C♯ |
| Em (iii) | B7 | V7/iii | D♯ |
| F (IV) | C7 | V7/IV | B♭ |
| G (V) | D7 | V7/V | F♯ |
| Am (vi) | E7 | V7/vi | G♯ |
C7 is the odd one: its leading tone, E, is in C major already, and it is the seventh, B♭, that makes it sound like a dominant.
An inversion’s figures go on the V: D7 with F♯ in the bass is V⁶₅/V, and the F♯ in the bass rises straight to G. A secondary dominant doesn’t always go where it leads: E7 going to F instead of Am is a deceptive move, like V to vi, and the tooltip says so.
A diminished chord can do a dominant’s work too. F♯dim7 is built on F♯, the leading tone of G, so it pulls into G: it is written vii°7/V.
In a minor key
A minor key takes its chords from all three of its scales (natural, harmonic and melodic), so in A minor, C, Dm, E7, F, G and G♯dim7 are all its own. A secondary dominant there brings a note none of the three has: C♯, D♯ or A♯. A7 going to Dm is V7/iv.
In a mode, such as D Dorian or E Phrygian, the chord sheet writes numerals only. Borrowed chords and secondary dominants are names from major and minor keys, and a mode’s chords do other things: E major in E Phrygian is the home chord of much flamenco, not the dominant of A minor.
The Neapolitan sixth
The Neapolitan chord is a major chord on the lowered second note: D♭ major in C, where the key has D. It is named after the opera composers of Naples in the 1700s, who used it often. It is usually played with its third in the bass, D♭/F, and so is called the Neapolitan sixth, written N⁶. It leads to the dominant, and its D♭ falls to B, the leading tone: a striking step down. The Neapolitan demo plays it in a minor key, where it is most at home.
Pivot chords: changing key
A modulation is a move to a new key that the music stays in. The smoothest way there goes through a chord the two keys share. In C major, Am is vi; in G major, it is ii. When the music goes C, Am, D7, G, the ear hears Am as vi in C. Then D7 comes, which C major doesn’t have, and the ear hears that Am was really ii in G. Am is the pivot: the chord sheet writes both numerals, the old key first, vi = ii · pivot, and → G major where the key changes.
Not every key change has a pivot:
- a direct modulation goes straight into the new key, as a song does when it moves up a semitone for its last chorus;
- a change of mode keeps the tonic and changes the scale, from C major to C minor, and needs no chord to lead there.
The tooltip on the key change says which it is. Key changes themselves are set on the playlist’s bar numbers: see Keys and modes.
Hearing them in the demos
The demos under File > Demos > Styles > Classical include short progressions that show these chords: Minor plagal (iv to I), Picardy third, Neapolitan and Chromatic mediants (major chords a third apart, as in film music). Songs are full of them too. Open the chord sheet of a jazz standard such as Rhythm changes and look for the yellow numerals.