Understanding single and double forearm rotation is an essential part of growing your technique as a pianist.
Here, tonebase Head of Piano Ben Laude will define single and double rotations on the piano and show you how to incorporate these into your practice routine.
Forearm rotation is the crux of the Taubman Approach to piano technique, and mastering the mechanics and application of rotation is essential to developing facility at the instrument. But the visible act of rotating the forearm one direction or the other should happen only in practice. These movements then get minimized and turn into invisible, unconscious reflexes that support your agile movements. Keep that in mind as I describe the movements.
Two directions of rotation
Let's start by going over the different directions and types of rotation.
The forearm can rotate the wrist and hand either clockwise or counterclockwise. For each hand, that means:
- Clockwise (LH: towards the thumb, RH: towards the pinky)
- Counterclockwise (LH: towards the pinky, RH: towards the thumb)
Here's where it gets a little tricky, but really not that tricky.
In many instances, you have to rotate both clockwise and counterclockwise to successfully perform the movement for the simple reason that you have to prepare the hand to rotate in the direction of attack. This requires you to rotate in the opposite direction so that you can swing back towards your target.
This is simple to understand if you just compare it to something like throwing a ball: you have to bring your arm and hand backwards in order to then throw forwards. Or, just imagine a catapult.
What I just described is called a "double rotation" in the Taubman approach. But there are actually two types of rotation: single and double, and even in the simplest contexts – like a C major scale – both types of rotation are pivotal to choreographing your movements in a healthy and fluid way at the keyboard.
Single rotations are used when the hand is already rotated away from the target key, so all that needs to happen is a swing back towards the key.
Think of what is happening in a successful trill, tremolo, or broken octave: each rotation in one direction automatically prepares the hand to rotate back in the other direction once the key is struck.
The aforementioned double rotations are used, for example, whenever you need to start a scale or arpeggio from a neutral hand position.
You must rotate away from the starting key first in order to then swing back down and strike it. Seymour Bernstein refers to this as a "swing stroke," (see 7:00 here) and when he demonstrates it (for example in his E minor Prelude lesson), it looks more like he's just lifting and dropping his hand. That's sometimes what it feels like, but underlying this movement is often a slight opening and closing – in other words, double rotation.
In practice you should exaggerate the movement so you can really feel your mechanics in action.
I would recommend you watch Bob Durso's tonebase lesson on rotation. He discusses single and double rotation (and preparatory motions) starting at 27:30.
Rotation in the C major scale
Knowing all this, it can still be hard to figure out if a note calls for a single or double rotation, especially when the hand is crossing between different positions in fast runs.
The ascending C major scale is a good place to get used to larger single and double rotation movements. Once you understand the mechanics you'll probably be able to apply it to many different passages.
Just looking at the right hand (I give the fingering in parentheses):
- C (1) - double rotation, because you have to begin the scale by swinging the thumb away from C (the pinky is your axis of rotation) so you can then swing back down with the thumb.
- D (2) - single rotation. Why? Because the follow through of the double rotation movement used to play the C had now automatically put your 2nd finger in position to swing back in the other direction to the D.
- E (3) - double rotation. Why? Because when you finish playing D coming from C, you now must continue to ascend on the keyboard, which means the way you rotated the hand to play the D (clockwise) is the same direction you need to swing to play the E. But you can't now, unless you rotate backwards again, ever so briefly, so you can then swing back down to E.
- F (1, thumb under) - single rotation. This is where things might seem confusing. Is crossing the thumb under really just a single rotation? Yes it is, and this is actually the "secret" solution to thumb crossings (when ascending in the right hand, or descending in the left) that students are often not taught. Once you finish the double rotation to play the E, notice how your hand naturally wants to follow through and end up in a place where the thumb has swung slightly under the 2nd and 3rd fingers, ready to swing back downwards. Well, it's as simple as that! It's just that you need to swing it back down to the F on the other side of the E. So long as you make sure your thumb isn't glued in position over the C, but has been calmly following along with your hand as you ascend the scale, then it should feel very comfortable to complete a single rotation back down onto the thumb. This brings you hand in one fell swoop to the next position, starting on F. The beauty of this rotational movement, is that it shouldn't even feel like you're "crossing under," just that you're following the most efficient direction of rotation and letting gravity take care of the rest.
- G (2) – single rotation, for the same reason as the D. After playing the thumb on F, your follow through has already put you in position to swing in a single direction back clockwise to the G.
- A (3), B (4), and C (5) - double rotations, for the same reason as the E. The thumb is now out of the picture and your 2nd, 3rd, 4th, and 5th fingers are being played in order in an ascending direction. So there's no way to avoid the double rotation. If you were to continue the scale, that's a different story. Then you'd play the C with 1, and it would be a single rotation for the same reason as the F.
For the left hand descending from C to C, all the rotations listed here are the same, since the hands are mirrored.
When coming back down with the right, or up with the left, it's basically reversed (except for the starting movement, which is always a double).
So, RH down or LH up would be: double (5), single (4), double (3), double (2), double (1), single (3 - crossover), single (2), double (1).
I can’t say it enough: these movements should be exaggerated in practice to help you gain the reflexes to perform the series of balancing acts across the C scale as efficiently as possible, so you can play at any speed (or articulation) with control. That's true of any rotational practice. The movements should be "invisible" and embedded in your mechanism once you're actually playing/performing at speed.
The principles I go over here generalize to any ascending/descending pattern, but obviously music gets complicated and it's not always so obvious.
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