The interval that quietly trips people up
You play sixths far more often than you probably notice. They turn up in melodies, in the inner and outer voices of chords, and all through the études — and yet, when I ask a student to play a run of them, they very often come out uneven. One is a little late, the next is slightly muffled, and the line never quite settles.
So this is really a question about how to play sixths on piano cleanly and at speed, and the answer starts somewhere most players don't expect. Not in the fingers. In the arm.
Why stretching and hoping doesn't work
Here is what usually happens. The player sees the sixth, spreads the fingers as far as they will reach, and hopes the hand lands in the right place. Sometimes it does. Often it doesn't quite.
The trouble with reaching for each interval fresh is that you are asking the fingers to solve two problems at once — find the distance and play the notes — in the same instant. That is a lot to leave to chance, and the hand pays for it. You get inaccuracy, because the shape is never the same twice. And you get tension, because a hand that is constantly stretching and re-measuring never gets to relax into a form it trusts.
Speed built on that kind of guessing falls apart. The moment the passage asks for evenness, the guessing shows.
The fix is arm-led
The real solution is to stop leaving the distance to chance. Before you play, program the hand's shape before you play — set the distance between the two fingers first, so the interval already lives in the hand as a fixed form. Once the hand knows the size of the sixth, it stops hunting for it. You never miss a distance you have already programmed.
Only after the shape is secure does the arm enter its role. And this is the part that changes everything.
The fingers play the sixths in parallel — interval to interval, legato, one after the next, holding the same form. The arm doesn't play the notes. What the arm does is move, and that movement is what gives you comfort and speed.
The two motions that carry the sixth
There are really two things the arm and hand do together, and it helps to feel them separately before you combine them.
The first is vertical. Between one sixth and the next, the arm rises and falls — a small up-and-down that carries the hand from interval to interval without the fingers having to grab or lunge. The arm lifts slightly, the hand travels, the arm sets it down on the next sixth. That vertical motion is where the ease and the speed come from.
The second is horizontal. As the fingering changes, the hand travels sideways across the keyboard — outward on 2-5, inward on 1-4 or 1-3. The sixth takes three fingerings in all: 1-3, 1-4, and 2-5. The hand shifts a little in each direction to keep whichever fingers you are using comfortably over their keys, so nothing has to strain to reach.
Through all of this, keep the upper voice fully legato. The top note of each sixth will often run 3-4-5 in a normal hand, and letting the arm carry that reach is what keeps the top line singing while the fingers underneath change shape. The melody on top should never break just because the hand is busy underneath.
The catch: this is not how you play octaves
Here is the distinction I most want you to hold onto, because it is the thing that trips people up when they bring octave habits to sixths.
With octaves, you lock the shape and the arm carries it a fixed distance. The hand becomes one solid unit — the same span every time — and the arm simply transports that unit from key to key, the way you would with an octave, where the shape locks and the arm carries it. The fingers barely move relative to each other. They are passengers.
Sixths are not like that. The shape holds, yes — but the fingers keep playing. Each sixth is genuinely played, finger to finger, legato, and the arm only helps.
It moves up and down and sideways to make the fingers' job easier, but it does not take the job over. The fingers stay active; the arm supports. Confuse the two and your sixths come out as stiff as blocked octaves, or as loose and vague as a hand with no form at all.
Where you'll actually meet them
It is easy to think of sixths as an études problem — Chopin's Op. 25 No. 8 is the famous one, a whole study built on them.
Scriabin's Étude Op. 8 No. 6 is the other side of the same coin: a deeply lyrical, singing piece built on sixths, beautiful and very hard, three demanding pages of it.
There the sixths are melodic, and the distances between them are large — the whole shape has to leap across wide intervals from one sixth to the next.
It is almost a perfect illustration of everything above: you hold the shape and let the arm carry it, smoothly and legato, across those big distances. Good arm movement is exactly what lets you play those wide melodic sixths beautifully.
But it is not just the studies. Sixths hide inside ordinary chords and inside melodies you already play, in the gap between the top voice and an inner one, and you meet them far more often than the repertoire lists would suggest.
That is the good news. Once the shape is locked and the arm knows its job, all those passages that used to fight you start to settle. The interval stops being a small daily gamble.
Try it
Take a passage with a run of sixths — or just play a scale in sixths, slowly, up and down.
- First, set the distance. Feel the two fingers find the sixth as a fixed shape before you play a note.
- Play the sixths in parallel, slowly, legato — interval to interval, keeping the same form.
- Let the arm rise and fall between each sixth. Small motion, not a lift — just enough to carry the hand.
- Shift the hand sideways with the fingering: outward on 2-5, inward on 1-4 or 1-3.
- Keep the top voice singing and legato the whole way — often 3-4-5 across the top.
- Only when it feels even and comfortable, begin nudging the tempo up.
If it starts to feel uneven again, you have almost certainly gone back to reaching for each interval with the fingers. Slow down and rebuild the shape first.
In short
Sixths come out uneven when you stretch for each one and hope. Program the distance between the two fingers first, so the shape already lives in the hand — then let the arm move up and down, and sideways with the fingering, to carry it.
The fingers play; the arm helps. That is the whole difference from an octave, where the shape locks and the arm does the carrying. With sixths, the shape holds but the playing stays in the fingers.
Where this is built step by step
Inside the Piano Fantasy Academy, the sixth is trained early. In Super Fingers Essential, exercise 17 locks the interval into the hand from the start — and later it returns, harder, near the end: real legato sixths with the fingerings 1-4 and 2-5, exactly the ones the études will ask for.
That is how the whole system works. Intervals are built from simple exercises up to real music, so that by the time you meet a sixth in a piece, it already lives in your hand and your arm already knows where it sits.
You can keep experimenting with this on your own, or follow a clear system that builds the sixth into your hand step by step.
