Lucyna Gaj
a new conception of piano performance
To play well, it is necessary to AD-JUST the keyboard to the hands

IDEA

Replaceable keyboards

G.L.C.F.

an alternative to the current standard keyboard in upright pianos and grand pianos
The hand of a concertiser (outline) 
for whom this keyboard is ideal, because he grasps a tenth (ten white keys) 
Standard keyboard of grand pianos and upright pianos
The hand of a pianist 
(my hand)
for whom this keyboard is a source of problems, because it grasps only an octave (eight white keys) 
The standard piano keyboard with a white key width of 22.5 mm is excellent on the low and average level of playing and education. But problems begin on the higher and top level of piano performance. This keyboard is ideal only for those who easily grasp (minimum) a tenth (10 white keys). For those who grasp only a ninth (9 white keys) it is much less perfect. And for those whose hands have not grown and who grasp only an octave (8 white keys) it is simply an instrument of torture. So this keyboard suits some players, but a majority of them finds it uncomfortable.
Nobody informs you during the purchase of an expensive instrument or during your education that you must master this problematic grasp of a tenth in order to play well on this highest level and think seriously of a professional career. If you grasp more, this is even better. Arthur Rubinstein, a well-known piano virtuoso, grasped 12 white keys freely. So did Chopin, Liszt, Horovitz and many, many others. To me, it is surprising that, although a cast of Chopin's hand exists, nobody has dared to make a develop a computer image of this cast to see what was the actual grasp of this piano genius. 
I studied piano at the Conservatory in Orleans and then at Ecole Normale-Alfred Cortot in Paris and no one has ever told me that in order to become a professional pianist, it is necessary to grasp a tenth, whereas I grasped only an octave (8 white keys) at that time. In spite of this problem, I was promoted to the 4th professional division in Ecole. Unfortunately, transition from the 4th to the 5th division was not possible, only because of the a/m manual problems.
In 2002 I learned by accident where the problem lies. Or maybe it was not an accident, but Mozart and my father. We were playing together Mozart's "Andante with variations" KV. No. 51. While we were playing, my father compared our hands on the keyboard and found the crux of the matter. Comparing our hands, he came to the conclusion that I should simply use a keyboard with narrower keys to play better. We hadn't got the slightest notion what kind of narrowing is required, nor did we know anything about a tenth. As far as a tenth is concerned, it was Chopin who helped us in 2005. We went to the 15th Chopin Competition in Warsaw and, as usual, to Żelazowa Wola. In a souvenir shop we bought the book "Życie Chopina" (The Life Of Chopin) by Kazimierz Wierzyński. The whole problem of a tenth was described clearly on page 37 of this book. Then we understood that the matter was more complicated than we thought. Why? All of the most magnificent piano works - concerts, sonatas, ballads or polonaises - were written by pianists who composed using large spans of their big hands. So, in order to play these works well, it is necessary to have a similar hands-keyboard proportion to those of the great musicians. If we cannot make it on the standard keyboard, the only soluton is to select a keyboard with appropriately narrower keys, which will help to fulfil the a/m proportionality condition.
Let's consider the example of a pianist (rather female pianist) who grasps only a ninth on the standard keyboard. If we narrow white keys from 22.5 mm to 20 mm, such a pianist will eventually be able to grasp a tenth on the modified keyboard.

This is confirmed by the following calculations: 
standard keyboard (white key width: 22.5 mm) ---- ( 9 x 22.5 ) + ( 8 x I ) = 210.5 mm 
modified keyboard (white key width: 20.0 mm) ---- (10 x 20 ) + (9 x I ) = 209.0 mm
As a result of narrowing by 2.5 mm, a tenth becomes narrower by 2.5 cm, i.e. more than the width of a white key in the standard keyboard. Consequently, you can have the impression that the pianist's hand has immediately become wider by these 2.5 cm.  
In order to check if our idea makes sense, we decided to present our idea to professionals and encourage them to construct prototypical piano keyboards. Unfortunately, nobody wanted to help us. Only the Pleyel company from Alex was initially interested in our idea. We waited one year for a specification of costs and conditions of the implementation of our idea. We thought that it may work. Unfortunately, the company went bankrupt at the end of 2006 and we were left holding the bag. So we could only rely on our own devices.
In January 2007 my father lost his patience and started to construct by himself the first piano keyboard with a white key width of 19.0 mm. It was crude, but I could play quite well on it. We could see immediately that our idea works. I helped my father with design works and the making of particular elements as much as I could. We worked in the kitchen that was provisionally adapted for a workshop. We decided to make another, more professional keyboard with even narrower keys and that's how a keyboard with a white key width of 18.0 mm was created. It was definitely more similar to a real keyboard and playing on it was even better. We had to try doing it on the grand piano. We bought a short Playel at a quite expensive price and made a 21.5 mm keyboard. And we modified only 82 instead of 88 keys. Since 82 keys were sufficient for Chopin in his time, why make more?
As a result of our experience gained during the construction of the grand piano keyboard that was much more difficult to make, we were certain that it was also possible to make other more reduced keyboards. However, we returned to the upright piano to make as fast as possible a keyboard narrower than 18 mm, i.e. a 17 mm keyboard, on which I can finally grasp a tenth and play freely. All of the above mentioned keyboards are shown on attached photos. I have also provided some links to YouTube videos. I will try to add some more photos and videos in the future.
I would like to present the problem via this website. Attempts to eliminate this problem were made already by Paul von Jankó together with Franz Liszt. In 1882 Van Janko invented a keyboard with six rows, patented as the Jankó keyboard, but it never caught on, because it differed too much from the traditional keyboard and required different fingering. However, its advantage was the fact that pianists who grasped an octave on the traditional keyboard could easily grasp a tenth on this one.  
Another interesting case in this matter is the story of Józef Hofman - an excellent pianist of Polish descent who had a career in the USA in the 1920s. Because his hands had not grown, he ordered 2 pianos with narrower keys from Steinway. Unfortunately, their degree of reduction is not known. Today similar projects may also be carried out secretly for some pianists, with the standard pressure force on keys being additionally reduced.

Since this can be done for some pianists, why not for all of them? 

Everything in the world is subject to improvements and modifications. Only the standard keyboard of upright pianos and grand pianos has survived many centuries, even though it may fit only around 30% of players. I'm sure that, considering our current technique, this important problem can and should finally be resolved.

New system

Generally speaking, everybody should play on a keyboard with such width of keys that would suit him/her best, rather than with the standard size that was invented a very long time ago. It is clear that anybody who finds the standard keyboard comfortable should still have the possibility of playing on it. The standard keyboard will continue to be an essential part of a piano, but each player will have the possibility of selecting another option that would suit him/her even better. Also, a system of adjustment of the pressure force on keys should be put to use. It was invented a long time ago, but nobody is willing to implement it.

The single-keyboard system must be replaced with a multi-keyboard system

How can it look like in educational practice? In music schools there are usually two pianos standing beside each other: one for the professor, one for the student. The professor's piano will have the standard keyboard, whereas the student's piano could be equipped with a G.L.C.F. keyboard. The professor and students grasping a tenth would play on the piano with the standard keyboard, whereas others would use the piano with the G.L.C.F.-20 keyboard. 

If I could (during my studies at Ecole Normale A. Cortot) play and take examinations on such modified G.L.C.F.-20 keyboard (on which I would grasp a 9th), I would obtain a Brevet d'execution after completing the 4th division (it is the most difficult and lasts 2 years, whereas others last only one year). With the Brevet d'execution and the previously obtained diploma in solfège, I could begin to give private piano lessons for beginners. 
I can imagine what Robert Schumann would say if he could know our system. Maybe he would only need 2 mm of reduction of white keys instead of those exercises that led to the paralysis of his right hand.