Harmony by degree

▶ Open in Aratu to hear the examples, change them and do the exercises

In the last lesson chords had names: Am, F, C, G. Harmony students often think another way: not "A minor" but "the sixth degree of the key". Writing by degree shows what each chord does, and the same progression works in any key.

The degrees of the key

Degrees are written in Roman numerals, from I to VII, counted from the key of the piece, which goes in key:. In C major, I is C, IV is F, V is G:

Try it▶ Hear it in Aratu

key: C major
tempo: 90
chords = | I | IV | V | I |

Upper case is a major chord, lower case a minor one. In C major the second, third and sixth degrees are minor: ii is Dm, iii is Em, vi is Am. The most played progression in pop is this one:

Try it▶ Hear it in Aratu

key: C major
tempo: 90
chords = | I | vi | IV | V |

Write key: G major in place of key: C major and listen: the same progression, now in G. That is how a song is moved to another key to fit the singer's voice.

Sevenths and other chords

After the degree comes the rest of the chord symbol, as on any lead sheet: V7 is the dominant seventh chord, ii7 the second degree with a seventh, Imaj7 the first degree with a major seventh. viidim (or vii°) is the diminished chord on the seventh degree.

Try it▶ Hear it in Aratu

key: C major
tempo: 80
chords = | ii7 | V7 | Imaj7 | viidim |

The ii–V–I is the most important cadence in jazz and bossa nova.

Minor keys

In a minor key the degrees change: in A minor, i is Am, iv is Dm, and V7 is E7, the dominant with the leading note:

Try it▶ Hear it in Aratu

key: A minor
tempo: 90
chords = | i | iv | V7 | i |

Chords from outside the key

A flat or sharp before the degree borrows a chord from outside the key: bVII in C major is Bb, the chord that gives that rock flavour. And a slash makes a secondary dominant: V7/V is the dominant of the dominant, D7 in C major, which leads to G.

Try it▶ Hear it in Aratu

key: C major
tempo: 90
chords = | I | bVII | IV | I | I | V7/V | V7 | I |

Rolling a chord

With :arp after the chord, its notes sound one after another, from the bottom up, like a harp or a guitar picked slowly. It works on any chord, by name or by degree:

Try it▶ Hear it in Aratu

key: C major
tempo: 70
chords = | I:arp | vi:arp | IV:arp | V7:arp |

With the guitar strum

Degrees work on the chords line of any instrument, strum and all:

Try it▶ Hear it in Aratu

key: D major
tempo: 96
guitar {
  chords = | I | V | vi | IV |
  strum  = D du -u du
}

Exercises

Write I, IV, V, I in C major, one chord per bar.

Exercise▶ Hear it in Aratu

key: C major
chords = | I | I | I | I |

See an answer

key: C major
chords = | I | IV | V | I |

The same progression by degree, but now in G major. Change only the key.

Exercise▶ Hear it in Aratu

key: C major
chords = | I | vi | IV | V |

See an answer

key: G major
chords = | I | vi | IV | V |

The ii–V–I cadence in C major: ii7, V7 and Imaj7, with the last one lasting two bars.

Exercise▶ Hear it in Aratu

key: C major
chords = | I | I | I | I |

See an answer

key: C major
chords = | ii7 | V7 | Imaj7 | % |

In A minor: i, iv, V7, i, with the last chord rolled.

Exercise▶ Hear it in Aratu

key: A minor
chords = | i | i | i | i |

See an answer

key: A minor
chords = | i | iv | V7 | i:arp |