Every now and again, you’re working on a piece and you hit a passage that keeps tripping you up and you don’t know why. When that happens, it’s a sign you are about to embark on some brain re-wiring.

I was learning this tune by Brazilian flute icon Altamiro Carrilho dedicated to Johann Sebastian Bach, actually a pastiche of Bach’s style, a gluing-together of some of his greatest licks, called O Eterno Jovem Bach. You can hear it here.

In the C section, (or Trio if you prefer a less medically loaded term), there is a direct quote from Bach’s Jesu Joy of Man’s Desiring (Cantata 147), originally in 9/8 and here played against the 2/4 choro rhythm. The last five bars contain a series of five rising modes of the melodic minor scale, or jazz minor.

The major scale and all its modes form a so-called “diatonic” matrix composed of three notes from one wholetone scale and four from the other (a “3-4 split’). The jazz minor on the other hand, borrows two from one and five from the other (a “2-5 split”). One of its modes has been dubbed the Lydian Augmented scale. It’s in the last bar but one.

So that was the passage that I tripped up on on my whole tone panpipes. It is not technically difficult, per se, but I found it hard to sing the last five bars by ear without looking at the sharps in the score. A flag went up!

So what was the flag trying to tell me?

We devote endless hours of practice to the diatonic matrix and the seven modes it generates. But the 2-5 split also forms a matrix, though it doesn’t have a name. By classifying the 2122221 scale as the ascending form of a minor scale we neglect to make a systematic discovery of its modes, even though they are extensively used in jazz.

The closest we come to the above passage in Taffanel and Gaubert’s 17 Daily Exercises is the E minor exercise, which artfully uses its own rules to switch between the ascending and descending forms of the melodic minor with passages of the harmonic minor, and all this in a mere eight measures.

But no systematic working of the 2-5 matrix. That was what my flag was trying to tell me.

It was saying: “Do it!”

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