Could you explain what the notions, "leggiero" and "legato cantabile" - actually mean to you?
As I think, you actually would like to know what they do mean for me, particularly in perspective of the Chopin & Neuhaus' Method...
Look, the piano technique cannot be heavy and difficult for the pianists – do you agree? If we would like to achieve such a fantastic easiness of the really master's level – we cannot practice the piano using weighty and incompatible technical tools. That is why leggiero was the most often used word in the Chopin's piano lessons. The technical contents of this word could be interpreted as a possible smooth, joyful and easy way of articulation of the piano sound.
The very significant aspect of this kind of leggiero, is the proper control of The Zone: a hand cannot be just fallen down to the uncontrollable keyboard's Zone – it should smoothly be put into suitable Zone via active participation of the liberated fingers and the adequately produced sound must fully harmonize with our real artistic requirements. The virtual motion in the gained sound must be present in its interior; a hearing activity has to virtually push the sound – like a wind, which "pushes" the sail.
Look at the sample below:
It has to be very clear for us all that if these virtual notes (above) become overloaded, theirs motion becomes slower and heavier – up to the moment, the whole action must be stopped. Therefore, leggiero – in its purely technical (one can say: mechanical) meaning, should play so great importance role in the piano system built after CHOPIN & NEUHAUS' orders.
Legato cantabile is being habitually interpreted as a kind of the very lyric articulation of the sound, as something that could remember delicate portamenti known from the operas of Bellini. In the Chopin & Neuhaus' System it should be define as the main schooling pattern of the sound articulation yet, which greatly helps to develop the real piano technique. Why so? Because it helps to pass over the whole piano instrumental difficulty: thanks to its use the main part of mechanic difficulty of the piano keyboard would totally be improved. But, it may happen only through consequent use of the whole power of artistic fantasy, its creativity and will. A keyboard for unskilled pianist is like a cat's smile for the greenhorn mouse... – it is like highly refined trap that can destroy one's hands if behind them does not exist any strong artistic (virtual) upholder. Leggiero in our Method should not be understood as something that produces a weak, silent, bloodless sound – leggiero is just related to the physical easiness, in any case – not to the purely aesthetical side of the piano playing.
Generally seen, according to my actual knowledge related to the problem, here exists the very harmful misunderstanding concerning exactly the legato-subject in the piano technical schooling. Many teachers again and again would like to follow the sorrowfully primitive mechanic way of legato articulation on the piano, described in the (unfortunately) so famous book of Malwine Brée. This very brief manual, frankly said, actually would not like to take into consideration the fact, a piano keyboard is equipped with the keys. The keys factually divide the entire scope of the sounds' heights into collection of (mainly) 88 unique sounds being put in such an order, in which each sound stays away from the consecutive next one precisely for half a tone.
To produce the real sounding legato effect of the actual bel canto quality, one cannot brutally keep the former key pushing in the same time on the next one, so the real interval would be heard for a while, besides – devastating a clarity of melodic development and polluting the articulation's precision. Instead of such an amateurish legato "treatment", here must be used a much more professional kind of the piano sound's handling, built on an image of the real bel canto vocal technique, which most basic standard is the fluent sounds' moving without greater pressure – just like the waves of sympathy would operate the entire process. No fighting, just flying! At the last end I feel, I should once again highlight the question of the leggiero, of the purely TECHNICAL LEGGIERO of course: the ffff dynamic mark given by Prokofiev should practically be completed with the leggiero-feeling inside of the pianist's hands – just THIS feeling differentiates the real piano playing technique from the real wood chopping, indeed. The ultimate goal of all the pianist's work should very seriously be considered, too: what is the real point of the ultimate interest of the practicing and performing pianist? Is it the artistic image of the performed music or the way, he is assured, he should move his hands in?
One surely becomes better acquainted with these issues reading the H. Neuhaus' (fortunately...) famous book, but as well, reading this interview with V. Horowitz, who in history of the piano in the XX Century represents the piano mastery in its best, we could greatly expand our piano instrumental knowledge.