Progressions

The Coltrane cycle, in every key

By Oliver Duschka, the developer of Drop2

Four bars that pass through three keys — the progression with a reputation for being unplayable. It is a reputation earned by the soloing, not by the chords: comped with drop-2 voicings the whole cycle sits inside a five-fret window and your hand barely moves. This page has the shapes, the band, and the arithmetic that makes twelve keys into four.

Four bars, three keys

Almost everything else on this site stays in one key. A ii–V–I leans and lands, a turnaround circles back, a blues wanders and comes home — all of it inside a single key signature. The Coltrane cycle does not. It picks three tonics that split the octave into equal parts, a major third between each, and visits all three before the fourth bar is out.

The pattern is strict, which is what makes it learnable. Each tonic is followed immediately by the dominant seventh belonging to the next tonic, so every bar is an arrival and a departure at once: you land, and the chord underneath you is already pulling somewhere new. John Coltrane built the device into his writing in the late 1950s, and it has carried his name since. In scale degrees it looks like this:

The shapes, voice-led

Here is the cycle on the top four strings, one drop-2 voicing per chord — the inversions that sit nearest one another rather than the textbook grips. There are six of them for seven chord symbols, because the last bar returns to the shape the first bar started on, and they follow whichever key you pick:

Watch the joins, because the reputation this progression has does not survive them. Leaving a key is the same move every time: the fifth of the chord you are on does not move at all — it is already the third of the dominant taking you somewhere else — and the other three voices each shift a half step. Going from Bmaj7 to D7, that unmoved note is F♯, sitting in both chords with a different job. Three semitones of movement for a change of key.

Arriving is cheaper still. Two voices hold across the join: the dominant's root becomes the new tonic's fifth, and its third becomes the seventh. Under them the flat seventh falls a half step onto the new third — the guide-tone resolution that every ii–V on this site is built from — while the fifth drops a whole tone to the root.

Add it up and the whole loop costs twenty-two semitones. Five of the six changes cost three each; one costs seven, and it is the only place in the cycle where all four voices move at once. Which of the arrivals that is depends on the key you are in, so it is worth finding by ear rather than by counting. Played in root position instead, the same six chords cost between a hundred and eight and a hundred and twenty-eight — roughly five times the movement for the same harmony. That is the whole argument for voice leading, and this progression makes it more loudly than anything else here.

Every sound on this page is the Drop2 app's own sampled guitar, bass, and drums — from the MuseScore General sound library, used under the MIT license.

Hear it move

The loop below is the app's Play-Along band — walking bass, swung ride, hi-hat on 2 and 4 — with the six voicings above comped on top. The bass is doing the work your hand is not: a new root every two beats, and twice in four bars that root is a new key underneath you.

Two things to listen for. The last bar is the first bar again, so the loop closes with no movement at all, and at this tempo the seam is genuinely hard to hear. And the harmony never sounds like it is wandering, even though it changes key twice in four bars, because every one of those key changes is announced by its own dominant a half-bar ahead.

Twelve keys, four cycles

Here is the part that pays for the practice. Because the three tonics divide the octave into equal parts, the cycle starting on any one of them contains the same six chords as the cycle starting on the other two — the same music, entered at a different point. Run that across all twelve keys and the arithmetic collapses: twelve keys, but only four distinct cycles in the world. Learn one and you have learned three. Every other progression on this site gives you twelve different sets of shapes; this one gives four.

The key selector above can prove it. Start in B, then pick E♭, then G: not one shape on the page changes. The same six grips come back in the same fret window, and all that turns over is where the loop is entered — each of these three keys starts it on a different one of its own tonics, so the cards begin in a different place and the names underneath them rotate while the shapes stay put. The other nine keys behave the same way in their own groups of three.

This is the same trick the diminished seventh plays, one level up. That chord divides the octave evenly into four and collapses twelve names into three chords; this progression divides it evenly into three and collapses twelve keys into four loops. Evenness is what does it, both times.

Four bars that stay home

For comparison, here are four bars of the same length at the same tempo that never leave the key — the turnaround, counted from the ii chord. The band, the key and the count are identical; only the changes are different:

The turnaround stays home and its four voicings cost sixteen semitones, four per change. The cycle visits three keys and costs 3.67 per change. The progression that travels furthest asks the least of your hand, which is not the trade anyone expects, and it is the reason these changes are worth comping long before you can solo over them.

Take it around the keys

Because there are only four cycles, the round trip is shorter than it looks. Pick a key, loop it until the shapes stop needing to be read, then move up a major third twice — the same grips, arriving in a different order — and only then go somewhere genuinely new. Four sittings covers every key there is.

The harder skill is not the grips but the count. At this tempo each chord lasts two beats, and the temptation is to look ahead. The cure is the fifth that never moves when you leave a key: find it, keep a finger on it, and let the other three voices do the traveling.

Where Drop2 comes in

The Drop2 app teaches the vocabulary this page comps with. Learn shows all four inversions of six seventh-chord qualities on three string sets, and Train calls a voicing and listens, through the microphone, to whether you found it — which is the part a page cannot do.

Play-Along, part of Premium, is a band like the one above with the guitar chair empty, and the Coltrane Cycle is one of the forms it loops, under Progressions, in whichever key you set. Lines, also part of Premium, runs the same form for soloing and names the guide tone to aim at in each bar — which on these changes is the difference between playing the cycle and guessing at it.

Next: The bird blues, in every key →