Swanilda’s famous waltz from Coppélia. The first harmonic change comes only at the very end of the phrase.

If you’re improvising or harmonising a melody, there’s a lot to be said for just sticking to simple harmonies, and avoiding chromaticism or excessive modulation for the sake of it. It’s not a competition to see who can fit the most chords in. On the contrary, dance music depends on a certain amount of harmonic simplicity for its dance quality and feeling of lift and lightness.

It was one of my dissertation students who first drew my attention to this: if you look at some of the most famous and well-loved waltzes you can think of, many of them of them follow the pattern of Swanilda’s variation, which is to stay on the tonic for 6 bars, and then move to the dominant only in bars 7 and 8. In the case of Swanilda, what then happens is the reverse, like a harmonic palindrome – 6 bars of dominant 7th, followed by 2 bars of tonic.

Strauss does it, and Tchaikovsky does it. Another variant is to stay four bars in the tonic, and four in the dominant. Whatever happens, you get very simple harmony with a bass line toggling between the 1st and 5th degrees of the scale, little more. I looked at Oskar Nedbal’s Valse Triste for ages, trying to work out how he had achieved such subtle and unusual beauty, only to find that most of it was down to what he doesn’t do – he never moves from a bass line of G and D in the first 8 bars;  and again, the harmony is tonic for 6 bars, dominant(ish) for 2.

Likewise, two of the most famous codas in the ballet repertoire, the one in Don Quixote pas de deux and the one from Black Swan pas de deux, sit on a tonic pedal for ages, and modulate properly only right at the end of the phrase.

Yet the temptation when you’re improvising or composing is to try and throw as many tricks as you can into 16 bars of music, like you’re loading your plate at the salad bar.  I’ve seen 16 bar compositions for tendu exercises that have already modulated to a remote key by bar 4 (with a change of key signature), chromatic inner voices and bass-lines, interrupted cadences, and hardly a simple tonic or dominant chord in sight. I’d like to say that the result is a real dog’s dinner, harmonically, but in fact, dogs’ dinners I’ve seen tend to make more culinary sense.

If there’s a principle to follow, it’s to remember that 16 bars of music in a dance class have to be imagined as being a ‘clip’ of something larger, not a self-contained miniature. In fact, who writes 16 bar miniatures? There isn’t enough time to develop and resolve musical tension, so don’t try.