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The Most Natural Movement Vs. The Natural Path Of A Key

10 years ago by
A Pianist
Partially, along the lines of the stuff I've already said here, there's another thing that occured to me that I think is one of the key fundaments that leads to a person's style of technique, from the very first note that they ever play. The fingers most natural movements are obviously inward grasping ones, as Alan says. However, these movements are not always in the path of the key. Notably, the more the finger has already curled up, the less productive a continuation of the natural grasping action can be. Even with flat fingers, the truest pulling action starts almost perfectly into the key, but starts to come more towards you almost immediately, if you continue the grasping action. I think the reason for problems in the movement is the intuitive attempt to 'correct' that indirectness- instead of finding a way of incorporating the simple action into moving the key straight down. I believe that the simplest starting point for technique is to understand the specifics of is it that makes the simple actions mechanically possible, in the hand, when you throw in the forces that are returned to you by contacting a key? Even when playing with flat fingers, I think this is a vital issue that underlines the whole of technique. Do you think in terms of the (although, almost certainly without any conscious weighing up of whether to use the natural movement or strive to move in the path of the key)- forcing the hand into more complex movements. The intent of downward movements STOPS the hand from being able to move naturally (no matter how accustomed the player might be to the simplicity of grasping) and the subconscious contrives a more complex means of moving the key more perfectly downwards. Hence, the strong natural actions are abandoned and weaker ones come in as a replacement. I think there's a lot to be said for the importance of understanding natural movements get thrown out of the window, the moment a person sits at a piano, before seeking to restore those natural functions. When playing with ultra-curled fingers, how can the finger bond with the key and apply a sizeable force, if you using a further grasping action to sound it? It simply can't. I've become pretty convinced that when I play with very curled fingers, the only way to direct that action into the key is to pull with the strong muscles at the knuckle, but to simultaneously try to the joints at the end (although this is a stabilizing force not one that leads to notable movement). Anything else and I slip off the key (or I have to dig in hard with a lot of pressure, to compensate for the inward pull). I'm not suggesting that this type of movement be banned, or anything, but would this complex action ever be a good starting point? I'm all for practising balance in such positions, but how can the movement of trying to play a key with a very curled up finger rely on 'natural' actions? I really don't think it's possible, without major 'corrections' to the path of motion. I'm thinking that with a lot of work on the slowest preparatory actions, from totally flat to comfortably formed (but where every action can remain inwards, without ever going so far as to stop those last two joints being able to act productively) you can get the feeling of this simplicity of inwards action, without any confusion resulting from emergency attempts to make the force more exactly downward. In normal playing, this would not mean forcing the fingers to be ultra-flat, but starting from the neutrally formed shape- so the simple inward action is mechanically productive at all times. Again this brings me back to weight though- as the finger cannot bond with the key without it (and following on from that, the natural action is cannot be fully productive unless the fingertip does indeed bond properly with the key, so that everything else moves around that point). With a theoretical anti gravity module attached to a human, they could not walk, as they could not generate enough friction against the floor- unless there were something else to press them down. Similarly with a harness holding your weight, you would slip across the floor much more easily (although every time you pushed up, the weight would actually become an issue again, despite the harness). If the friction is not generated by weight, you have to push instead, to get it. For this natural inward action of be used (without prompting slippage), there has to be just the amount of weight available for the finger to bond with the key. The release has to correspond perfectly with what the finger does, for it to perform it's most natural action. You wouldn't simply cut the 'harness' off and use full dead weight at all times, but neither can the finger's action create the friction to bond with a key, unless you are using just enough of the weight. Rationally, only the correct degree of release can allow a natural finger action to function productively. Small as the weight may be, you can also underdo it, if the equivalent of the 'harness' witholds too much. I've been finding this approach very helpful for the left hand in the last movement of the Scriabin 3rd sonata. I have to remember the finger's natural action (in ultra slow work), and never allow myself to slip into bad habits by thinking "move that key downwards". Everything is based on pulling inward in the simplest most natural way (as if you were just doing it in the air with no thought of moving a key). Sometimes I feel the fingers are working very hard, so I need to lighten the released weight (although, sometime I want to deliberately work them a little harder than would be possible at speed, in preparation for lightening more afterwards). But sometimes I feel the most natural action leads to slipping, thanks to inadequate weight to achieve good friction. The arm usually starts "holding" to compensate for that, rather than allow them to keep sliding. If I get the corresponding weight just right on each one, however, it makes the finger's role extremely simple and the arm stops trying to compensate. I'm not dismissing more complex movements outright, but I think that this an extremely simple way of understanding the absolute basics of how to make it possible for the finger to get on with its most natural function, without falling into the trap of subconciously contriving unnecessary complex (and less efficient) ways to contrive a perfectly downward movement. I think this is the simplest possible way to understand what sets up the possibility for a finger to get on with what it's anatomically designed to do- without the specific mechanics of the piano tricking you into abandoning the simple action. I'm not suggesting this a magical "do this and all the details will just evolve" but it's making everything vastly more simple and bad qualities of movement are considerably more easy to both detect and correct. I'm going to use this rational explanation of to use the hand in it's most natural way as the most basic fundamental in my own teaching- although I'm certainly going to continue to use Alan's exercises to contribute towards developing the interaction in the long term. Right now, it's a very useful and simple guide for keeping me on track with the actions that I'm already capable of, but which don't kick in all the time on auto-pilot. But I suspect that consideration of this intuitive but unwanted desire to 'correct' the the natural path of the finger could have massive benefits as one of the absolute starting points for technique.
10 years ago by
A Pianist
I,m at the moment trying to "clean up" dirty passages here and there in the repertoire- These dark bars were you cover up to hide the inability to play them straight. A task were almost any kind of technique however strange it may seem is allowed. Your description above of "extreme curling" and "simultaneously try to straighten the joints at the end " is something I find extremely useful momentarily. For me it feels like the way you describe it just comes naturally and I do beleive if you do it just like that it's your lumbricals that's really involved so there is no extreme pressure on the tendons. You put strain on the tendons only if you play à la Jael with extreme curling and high articulation. An underestimated technique as well if you ask me. I've followed the interesting debate between you and Alan, not beeing a skilled teacher like yourself it's sometimes difficult to grasp but my amateurish impression is that at some level divergenses are small or non-existant it's just a difference in focus and priorities. I'd say your findings about weight is one aspect which independantly of other aspects leads to nothing. The rotational elemnts for example is an important aspect for a beginner whatever method you use you don't want rotation to work against you. Pianoplaying is indeed the art of micro or rather nanomovements. How many times have you solved an impossible bar with a tiny change in position. Weight and bodymovement is if you ask me not a sine qua non if you work as a longe-pianist you don't orchestrate and you hardly ever go over mf. I admire Art tatum he was a genius but I don't think he had developped the skills to play Rach#3.Why should he? In the end I beleive that if you do want to reach a higher level there is only one way and that is to develop a very able and strong hand and that takes decades. Liszt insisted on this aspect even if he was one of the fathers of armweight etc. His approach was "anything is permitted". It's not a coincidence that russian musicians are very reliable when it comes to technical skills. At least before you didn't make "the cut" if you didn't pass scale double thirds etc-examns. You can't change the hand like Schumann was trying to but you can indeed develop a high degree of independance and strength a sine qua non. Many of Liszt's exercises (I beleive they are his) are obsolete he found out that himself in later years but I still think some are very intelligent especially since I've been working with Alan's methods and have understood the anatomical functions of the hand-that is what you can do like working with your lumbricals and can not eg "exercise" your tendons.Etc. I'm not a teacher and I don't know if it is recommendable to start working up the hands and fingers of young people but at some level I think that aspect is important if you aspire to play more demanding repertoire. Otherwise your reflections about weight counterforce etc is well worth a web of it's own- is it up already? Like a spin-off from Alan!
10 years ago by
A Pianist
Your description above of "extreme curling" and "simultaneously try to straighten the joints at the end " is something I find extremely useful momentarily. For me it feels like the way you describe it just comes naturally and I do beleive if you do it just like that it's your lumbricals that's really involved so there is no extreme pressure on the tendons. You put strain on the tendons only if you play à la Jael with extreme curling and high articulation." Ah, but I'm not either dismissing this or suggesting that it might be strainful, necessarily. I'm just wondering, is this really the most natural action for a fundamental building block, or is it better as a more advanced variant? Actually, I'm very glad that I thought about this motion in more detail, because I do intend to capitalise on it very deliberately at some point. But first, I want to build up the ability to have complete willful control over whether I use the finger's natural inward actions, or contrive a means of moving more exactly downward. I don't think it's healthy to let the instincts choose for themself. Otherwise it can just be a somewhat less extreme version of when you see a kid pressing a key as if it were a button. Is it really more 'natural' to contrive the means for a perfectly downward movement, or is it more natural to start with the hands most natural inward actions and then find a way to channel that into a productive downward motion of a piano key- without having to distort it? I've been wondering myself whether it might just be the lumbricals, but I do strongly suspect a little straightening action too. Try if you take a heavily curled finger in the air and pull back only from the lumbrical. Firstly, it will likely feel a bit weak and with a rather small range of motion, compared to if you did the same action from a straight finger. Secondly, if you imagine having lined up over a key, the action would scarcely go into it at all, because it's so much back towards you rather than down. So even with the lumbrical alone, it would be hard to channel this movement into a key. With such a small surface area to bond with they key and with such an indirect path, I believe that it would require vast amounts of downward force (either through weight or arm pressure) to make it possible for the fingertip to bond with the key. Slippage would be extremely likely, without a notable downward force- which the finger provides very little of, if it uses it's natural path. Now try a similar thing in the air still (from the lumbricals again), but imagine a perfectly downward action at the fingertip. Can you feel how the end joints actually have to straighten, to go in the right line of motion? You're probably so used to it, that it seems normal, but can you detect the difference? Also, try this same thing in the air, sometimes starting as if lined up to play with flatter fingers and as if to play with a higher wrist or a lower wrist. Basically, the flatter the finger and the lower the wrist, the more directly the natural inward actions are poised to transmit energy downward into the key. I'm not saying this means you can never sit too low or start with too straight a finger, but it makes me wonder about sitting high and with heavily curled fingers. Is such indirectness and the necessity of resorting to straightening actions really a good basis for technique? As I say, I'm not seeking to ban some straightening actions on those grounds, but I think this dilemma between the natural use of inward functions and the desire to 'straighten' the force with more contrived actions should be understood- in order for less natural actions to be done in a productive way- rather than as a subconscious result of thinking 'the key moves downwards so I've got to aim the force exactly that way'. Also, only starting from flatter fingers allow a big sound in loud chords, without the arm pushing. I've recently discovered that I can produce very big sounds in the loud chords before the coda of Chopin's fourth Ballade, solely by squeezing inward from touching the key and releasing enough weight for the fingers to act against- ie. not visibily 'dropping' or 'pushing' at all! All you would see is the finger action. This both gives you the whole range of the natural inward action and makes the force fairly direct. The action is actually extremely natural. But if you are not used to it, it feels difficult. Surely this simple inward grasp should simply be a more extreme example of a "normal" action, rather than something totally different? If you do not train yourself how to employ the most natural action as one of the most standard things in playing, how can it evolve? "I've followed the interesting debate between you and Alan, not beeing a skilled teacher like yourself it's sometimes difficult to grasp but my amateurish impression is that at some level divergenses are small or non-existant it's just a difference in focus and priorities." Yeah, I think we're simply looking at a rather similar product from different perspectives. The only thing where I think we really disagree is whether there is value in perceiving the balance between the returned forces and the weight. As long as the difference between this and collapsing (which is a FAILURE to find the very balance I'm talking about and something altogether different) is understood, I believe there definitely is. "How many times have you solved an impossible bar with a tiny change in position." It can happen, but what if the basic action remains unchanged? I realised yesterday, after writing this, that my fifth bonds really very poorly with the key virtually all the time. It was only after writing this, that I realised how poorly my fifth is actually using it's stronger functions. And not only did I notice that, but I realised that this is partially because it begins virtually every action with a tiny slip along the key! By the end of yesterday, my fifth finger was more tired than it had been in ages- because I actually started working the muscles against something, throughout the entire action. In order to use the natural inward function to the full, this bonding with the key needs to be done flawlessly. "Weight and bodymovement is if you ask me not a sine qua non if you work as a longe-pianist you don't orchestrate and you hardly ever go over mf. I admire Art tatum he was a genius but I don't think he had developped the skills to play Rach#3.Why should he?" But that's just less release of weight. I think Art Tatum was as sensitive to weight as anyone. He didn't use extremes of if, but balance must occur in everything. Try locking your arm still and playing rapid legato PPP scales. Then try relaxing your arm heavily and doing it. Neither works. Only correctly proportioned use of weighting can allow such things to be done with stability. What has that got to do with the hand? Well, it has to match what the hand does (and the hand has to work very well, of course), but balance doesn't automatically come from thinking about the hand itself. The only people who don't need to think about that are those who can simply do it already. It's far harder to gauge the release of weight in the type of passages that Tatum played than in Rach 3- if you are to eliminate such typical flaws as bouncing away from the keyboard, locking the arm for stability, fingers slipping across keys etc.. Bonding with the key is extremely difficult in the light passages that Tatum did. This is definitely related to release of weight, in mechanical terms. The release may be smaller than in loud passages, but if you miss the balance on either side, everything falls apart. It's not the case that you can only fall into the trap of releasing too much weight. The fact that the release is so small in quiet passages makes the danger of releasing too little even greater- just the same as it's easy to release too much. It's an extraordinarily fine balance and works on both sides. If the weighting is not right the hand also works less well. The ability to bond with the key at the fingertip (which determines how well the hand works) is intrinsically linked to proportioning of weight release in response to the finger. Skittering along the keys (a very common problem for such light passages) cannot be blamed only on the hand or only on incorrect weighting. The two are inseparably intertwined. Release determines what the hand can do and what the hand does determines how much release is required to maintain balance. "In the end I beleive that if you do want to reach a higher level there is only one way and that is to develop a very able and strong hand and that takes decades. " Maybe, but I've already felt my fourth and fifth working substantially better, simply from noticing the habit of contriving downward action and the tendency for it to slip when it does actually pull on it's natural line. Just the most miniscule of slips means the difference between working the muscle productively and not using part of it's range at all. You have to understand the basis for movement, to develop productive strength. I think there is great value in being aware of the physical reasons why motions so frequently deform slightly from the most natural actions- and what adjustments make a return to the natural actions physically possible. Then you have total willful control over which one to choose in any situation. No amount of strength in the hand would compensate for poor efficiency of transmission, if I started with curled fingers in those chords in the Ballade. I'd have to push from the arm, if I didn't use a means to transmit energy via the natural function of the fingers.
10 years ago by
A Pianist
Just been practising both movements and it's interesting to note the differences between them. I think that that sensitivity to the weight issue is especially important, when using the purest natural finger action (where the finger starts with a slight curve and every joint acts at least slightly inwards). The indirectness of the inward action means that either the finger wants to slide a little, or the arm wants to be drawn forwards. Releasing just a small amount of weight is of key importance here- felt in terms of the hand being pulled backwards though (like when relaxing the whole arm until the palm slips off the keys), not in terms of downward forces (which would likely be an illusion of 'gravity', that actually stems from muscular pressure). It's a kind of weighing up backwards forces against forwards ones- in a way that 'corrects' the indirect motion of the finger's natural path and gives very efficient transmission via what would seem to be a naturally indirect motion. However, I think that the one that is felt to be aimed directly into the path of the key (via a tiny straightening action in the end of finger itself) is actually very useful too. Because the path is so much more direct, I think the weight issue sorts itself out more easily. If directed in the perfect downward line, the finger is not inclined to slide backwards via it's action- meaning that there's less of an issue in terms of balancing weight against the forces that result (or at least, you don't have to be anywhere near as concerned about judging release of the arm to cancel the force, as there is a vastly wider margin in which things will balance- compared to the more precise balancing in the former example). I think that this type of action works more easily by itself, without intricate thought. It basically eliminates the forward/backward action and confines the movement to a single up/down plane. Maybe Alan uses a fairly directly aimed finger motion more- hence the skepticism about the necessity of matching up the backward and forward forces, as I've described- that would have to be done for the purest use of the finger's natural actions? I think both are actually very useful. However, I definitely want to make sure that I can do the natural action of the finger's path more consistently, without unwittingly slipping into the more exact downward action or sliding along the key. I do think that the former approach gives the muscles more quality of training, due to how they interact with some of the arm's weight- nothing to do with a collapse of weight here, where the fingers would be worked less hard. However, I'm going to continue to experiment with both. The latter explains how it's possible for those who sit extremely high and play with high wrists to access the keys properly- which I'd always been a little puzzled by. However, it still has uses when playing with a level wrist. However, I think that the sheer directness of the single plane of motion could be rather heavy going for loud playing. I think that the first approach is much more inclined to cushion the results of the most intense actions- rather than simply stop them dead in their tracks. Also, it occurs to me that it's not necessarily a case of using either one or the other. If you can do both of the extreme ones, it's possible to weigh up different levels of directness against the purity of the finger's natural action. There must be many levels in between, where it's not quite the finger's most natural inward action, but where the force is not necessarily directed flawlessly downwards either.
10 years ago by
A Pianist
Andrew, I love these posts and second Eric's feeling that they are worth a website of their own... but my thought was, are you going to write a book about this? Because I think there is definitely one basically already written in all your posts here... I especially feel that this paragraph is just brilliant. Bravo! AFF
10 years ago by
A Pianist
Andrew, I love these posts and second Eric's feeling that they are worth a website of their own... but my thought was, are you going to write a book about this? Because I think there is definitely one basically already written in all your posts here... Cheers- maybe at some point. I definitely want to try to organise some of the ideas on a website at some point, but perhaps it would even be worth having a go at a book eventually. I'm going to have to go back through these at some point and organise the ideas into a number of themed essays (hopefully with pictures and possibly short videos to illustrate the points that are less easily done in words), but I'm still changing my mind on so many things, I think it's going to take a bit of an effort to get something into a form that is both clear and (hopefully) permanent form.
10 years ago by
A Pianist
Well you can always recant in a later book, like I did about ulnar deviation... Will you call the book "Dancing About Architecture"? AFF
10 years ago by
A Pianist
Well you can always recant in a later book, like I did about ulnar deviation... Will you call the book "Dancing About Architecture"? AFF Yeah, that would certainly be a nice title! Incidentally, I'm realising that the downward thinking extends even further than I'd realised. I think that thinking too much about moving the key straight down also overlaps with the tendency to simplify gravity- where you end up pushing down, thinking it's use of gravity, because excessive thought about downward motion. I think that aiming to move the finger straight down is extremely likely to spill over into subconscious arm pressures, which I think makes it even more important to start with finding a way to transmit the purest finger pull, before aiming to move in a way that straighten the forces within the finger itself. I've found op. 10 no. 1 works spectacularly better than ever before today. Coming down, it's very easy to aim down too much through the tip of the fifth finger. I think that this subconcious tendency to direct the finger downward has also led to the finger collapsing ever so slightly and reduced the legato. After working a on very slow practise, where the main thought is to pull in the finger's path (and release the wrist enough to compensate for the enormous forward pull that this transmits to the arm), rather than move the key down, my hand quite literally seems to have changed it's shape entirely. My knuckle seems to have almost instantly become the same height as the others. I think that something about that persistent subconcisious intent to aim the finger downwards was forcing my knuckle to keep drooping. Odd as it may sound, that seems to have vanished almost instantly. Of course, this is all extremely similar to what you showed me- so all credit where it's due for the basis for this. However, I think the addition of full concious awareness of the difference between the extremities of the purest finger based movement and the purest key directed motion has literally made an instant difference to the consistency of putting these qualities of movement into practise. I think you have to understand what would actually make you abandon a natural function in the first place, to have the easiest time restoring it. I think there was a subconcious habit that kept coming back as soon as I started playing, no matter how many times I might practise standing up the fifth. All the time it was probably in the back of mind that 'the key goes that way' and my subconscious couldn't quite reconcile the (seeming) contradiction by itself. Incidentally, along these kinds of lines, I had a theory a while ago about the idea of slanting the hand towards the fifth for big itnervals. I was initally extremely skeptical about this, for op. 10 no.1. Doing this the wrong way in the past had made my fifth lifeless for a long time. My problem would be that if the fifth leans sideways, it's natural pull would not be into the key, but notably sideways (adding all three planes of movement to its natural path!). In this case, if thinking in terms of moving the key exactly down, the finger would basically have to do a gravity collapse, or have the arm prod it in. To contrive a downward finger action becomes literally impossible. However, if you still pull from the finger in it's natural indirect path (and forget the downward direction of the key) it actually helps pull the whole arm across. If you use the resultant force positively, (instead of stiffen against the sideways force, letting the finger remain on its side) it will pull you towards a position where the finger is standing more conventionally- and help bring the thumb across. So, although it's generally valuable to aim for just two planes of motion (so you're not forced to stiffen against sideways forces), there are situations where using the third plane can actually have real benefits. Thinking about the very most extreme example of the finger's natural action has made this work even better. It's as if you barely notice that it started a little slanted, because next thing you know it's already pulled itself into a more stable position. It's basically a fully 3 dimensional branch-off in terms of the same discrepancy between aiming for the finger's natural movement or aiming the key down. The same thing applies especially to that horrendous left hand in the Scriabin 3rd sonata. I'm no longer feeling that I stiffen anything into the key with an outstretched 5th finger. That used to lead to a whole lot of effort. Despite the seemingly counterintuitive notion of pulling in the finger's natural path (when it's starting practically entirely on it's side!) this both draws the finger closer to a more conventionall aligned position and draws the rest of the arm to meet it- as long as you don't fight against the resultant force by thinking 'just move that key straight down'. The more purely it comes from the finger's natural action (even though this seems an extremely indirect path into the key) the better. I think this is why you so rarely see professionals collapsed sideways onto the fifth. If they have to start from that position, they use the finger's natural action to pull themselves straight back out of it, as if that slant never even happened in the first place. I think this is a rare spot where overholding is bad- because the finger's natural action needs to pull you away from the outstretched position at once. Overholding would likely emphasise collapsing over it, not proper finger action. Instead of trying to force yourself to feel as if you're aligned 'over the top' of the fifth with stiffening, you immediately pull yourself towards a position where you really are feeling balanced over it. Incidentally, I remember you said something about left-brained versus right brained. I wonder if this is an issue with this specific type of thinking? It makes sense that a right brained person would always intend to move the key straight down in the path it's supposed to go (unless they think through the problems that arise from doing so, in more detail), but a left brained person might be more inclined to start based on qualities of movement. I don't think rational thought would usually be likely to hold a person back, but it may well be that the most rational thinkers could be held back here- unless they fully appreciate the complexity that arises via the discrepancy between the path of movement and the hand's natural function. No rational thinker is likely to aim for anything other than the purest downward movement- unless they have a rational cause to do otherwise, of course.
10 years ago by
A Pianist
However, I think that the one that is felt to be aimed directly into the path of the key (via a tiny straightening action in the end of finger itself) is actually very useful too. The presentation below might be interesting to you, as it discusses just this type of touch: ocd BTW, that web site has many articles that I have found useful.
10 years ago by
A Pianist
However, I think that the one that is felt to be aimed directly into the path of the key (via a tiny straightening action in the end of finger itself) is actually very useful too. The presentation below might be interesting to you, as it discusses just this type of touch: ocd BTW, that web site has many articles that I have found useful. Very interesting! There are lots of very similar conclusions and thought processes to ones I've been going through myself. It's interesting to see someone else running through such similar thoughts. The point about the collapsing end joint ("The more the teacher says to curve the fingers, the more pronounced this shape becomes!") is another point that I thought about in exactly the same way- if you over curl the finger you basically have to go back to square one by straightening the whole finger again, before you could ever fix the collapse. I do fundamentally disagree on one thing though: Transfers energy more efficiently because (a) It uses two short levers instead of one longer one - compare a car jack. (b)The finger tip is moving in the same direction as the key and there is no friction. I think that a fingertip which moves too "perfectly" in the path of the key is actually less stable than one that slightly pulls on the forwards and backwards plane, but which is stabilised by generation of friction. Too much indirectness compromises the efficiency to transmission and risks finger slippage. However, I think that excessive directness may actually make it rather harder to stabilise the arm (making holding more likely). It also means that there is less scope for absorption of the impact, when it land absolutely head on. I'll have to see if I can find contact details for the author and send him my theory sometime (where the finger's action is deliberately slightly indirect, but the arm's response is used to direct the action more directly into the key), as I'd be interested to see what he might make of it. I think point a is also slightly simplfied there, as it assume that there are only two levers involved. If the fingertip bonds with the key properly, EVERY other lever in the arm will be slightly affected by the finger's pull. While the response is actually negligble (due to the sheer amount of joints it will be acting on) I think this still makes for a world of difference compared to trying if you try to force a spatially "fixed point" to arise anywhere in the arm. I think that the only entirely spatially fixed point should be that where the finger contacts the key. Rather than make that happen by confining the motion to an exact downward plane, I think there's a lot to be said for figuring out how to balance out forces on the forward/backward plane, via the entire arm.