Relative minor, relative major

Every major key has a relative minor key. Think of it as an evil twin sibling. Relative minors are very widely used but not so widely understood. In particular, there’s a lot of confusion around the fact that major keys and their relative minors share the same key signatures and (mostly) the same pitches. But they sound and feel completely different. How can this be? Let’s dig in.

Here’s the C major scale. Click the image to play it on the aQWERTYon.

C itself is the tonic, the root note, harmonic home base. You can make a C major chord by starting on the tonic and going around the circle clockwise, adding every alternating scale tone: C, then E, then G. The other most important chord in C major for Western tonal theory purposes is the dominant chord, the one you build on scale degree five. In C, that’s the G7 chord, the notes G, B, D, and F. The active ingredient in this chord is B, the leading tone in C major. It’s considered to be a source of tension as it pulls against the tonic, and the convention is that you want that tension to be resolved.

If you rotate the C major necklace three steps clockwise, it becomes the A natural minor scale:

C major and A natural minor contain the same seven pitches. So what is the difference? It comes down to emphasis. If you treat A as your central pitch, then this collection of pitches sounds like A minor rather than C major. You can do this in a couple of different ways: you can drone or repeat A, you can start and end your melodies on it, and you can make sure that it occurs in metrically strong positions.

European classical composers found the natural minor scale to be unsatisfying. You can emphasize A all you want, but this pitch collection will still gravitate toward C major. They felt this way because A natural minor has no leading tone. So their solution was to give it one, by raising G to G-sharp, thus transforming A natural minor into A harmonic minor:

This scale sounds very different from A natural minor! There’s the big jump between F and G-sharp, which sounds more like Middle Eastern music than European music. You can build some very satisfying key-establishing dominant chords using harmonic minor. You can make E7 from the notes E, G-sharp, B and D. You can also make G#°7 from the notes G-sharp, B, D and F. Either chord will make the (European or European-descended) listener strongly expect A as the central note in A minor. You might confuse A natural minor for C major, but there will be no confusion about A harmonic minor and its G-sharp.

Here’s a diagram showing G7 resolving to C and E7 resolving to Am, with their respective leading tones resolving to their respective tonics:

Here’s a guide to relative majors and minors and their dominants in music notation:

Here’s a diagram showing all twelve major keys (the outer ring) and their relative minors (the inner ring) arranged around the circle of fifths.

The diagram also includes the dominant chords for any major or minor key. Take any key center and look at the note that’s one slot clockwise from it. That’s going to be the root of your dominant chord; just stick a “7” on it. So if you want to make people expect to hear G major, play D7; if you want them to expect F major, play C7; and if you want them to expect E-flat major, play Bb7. The minor keys work the same way: for any minor-key root, the root of the dominant chord is in the next clockwise slot. Just remove the “m” and replace it with “7.” So if you want people to expect G minor, play D7; if you want them to expect F minor, play C7; and if you want them to expect E-flat minor, then play Bb7.

But wait. G and G minor have the same dominant chord. So do F and F minor, and B-flat and B-flat minor. How do you know that a given dominant chord is going to resolve to major or minor? There are some context clues. If the song started on G, then D7 will make you expect to return to G, but if the song started on Gm, then D7 is going to make you expect to return to Gm. The melody matters too: if the melody notes on top of D7 come from the G major scale, then you should expect it to resolve to G, but if the melody notes on top of D7 come from G harmonic minor, then you should expect it to resolve to Gm. That said, the ambiguity might still remain, and you can take advantage of that fact to pleasurably fake people out. Classical composers loved to resolve a dominant to a major chord when you expect a minor one.

Okay. So. How do you move back and forth between a major key and its relative minor in a satisfying way? The simplest method is to play the tonic chords back to back. If you are in C, just follow the C chord with Am. If you are in A minor, just follow the Am chord with C. That works fine, but it lacks drama. The cool thing to do is to precede each tonic with its dominant. In C, play the C chord, but then play E7. The G-sharp in the chord will sound dissonant and alarming, because it’s outside of C major. But then when you play Am, the G-sharp will retroactively make sense and the listener will feel reassured. Finally, play G7 to smoothly pivot back around to C. This kind of progression is a standard trope of gospel music. Play it with some swing and groove to maximize the effect.

This song takes you through the relative majors and minors in all twelve keys:

Here’s the score. The minor-key leading tones are in green. The leading tone for the next key around the circle of fifths is in blue.

Let’s break down the first few measures.

• Measure one starts with C. Then comes E7, the dominant chord in A harmonic minor, setting us up to expect Am.
• Measure two starts with Am, as expected. Then comes G7, the dominant chord in C major, setting us up to expect C.
• Measure three starts with C, as expected. Then comes E7, setting us up for Am again.
• Measure four starts with Am7, an extended version of Am. Then comes D7, the V chord in G major, setting us up to expect G. (The Am7 retroactively sounds like the ii chord in G major.)
• Measure five starts with G, and the cycle begins again, but everything is transposed up a fifth.

If you really want drama, start in some major key, play the dominant of the relative minor, and then… don’t resolve to the relative minor! Like, in C, play E7, then resolve to F. It sounds amazing! But that’s another post.