Here I am, after 4 intense days of practise: around 6 hours Saturday and Sunday, maybe 2 hours Monday and 4 hours Tuesday. Here's my share of experience.
Before reading the method, I was already practising and playing the Mozart's Sonata K333 (1st mvt), the Schubert's Rondo of Sonata D959 and the Schubert's Impromptu op.142 n°1. I wanted to test the method described here. So I began with the Bach's Invention #8 as M. Chang said in his book: play HS, alternatively RH and LH (right hand and left hand), through little sections of about 3 measures each, and always without pedal. The most important thing to do here is to memorize while practising the sections. At the end of the piece, I knew both hands by memory. It was easy because when I was a kid, I had to work on this piece, so this was some kind of re-memorizing after years not playing it. I think that it tool me 10 minutes.
In every section, I played until reaching the final speed, because you have to master HS (hands separate) at speed in order to work HT (hands together) with a slower speed (70% of HS speed). I began to practise HT a little bit then I worked on the other pieces (the Mozart's sonata and the Schubert's rondo). Because I already worked them, but only HT, it felt like going backwards at first. But I realized that I missed a lot of chance to practise the difficult passages in order to master them, not just playing them roughly, with hesitations, making mistakes.
At the end of each piece, I tried to play at a slow speed to respect the Post Practise Improvement (PPI) rule. That's a real effort to do, because you work a long time on a piece, about 1 hour, and then when you want to switch pieces, you have to play at a slower speed the same thing. Maybe there's something to review here: planify better the practise session in order to anticipate this "slow moment".
After 6 hours (spread during the whole day), it's harrassing for the brain. I didn't sleep well, because my brain was so active.
I played first HS. Yes, I forgot to do the Mental Play (MP) before playing: close your eyes, and play in your head the 2 hands, paying attention to the notes played, the fingering, and the tones. I don't respect the tones on the sheet music I got, because Bach didn't put tones on it originally. I prefer keeping the staccatos that I learnt with my teacher a while ago.
Then I practised HT, section by section, at 70% of real speed. When it was OK, I started to work HS at 150% speed. This is where you have to speed up your memory to anticipate the difficulties, the "flubs". It's not hard HS, it's hard HT. Then I could practise HT at 100% speed.
Then I started the Invention #1, same thing: play HS, in little sections, without pedal. The harder part is the LH with the quadruplets all along. Then I tried a bit HT at a slow pace. But I tried HT 70% speed without the score: it's really really confusing and you need a lot of concentration to do that. It took me a very long time to play correctly simple sections, and I asked myself: when you start to practise HT, should you read the score or should you play it by recalling the HS learnt by heart? On the first case, it's for me sight reading (and somewhat easy for me), on the second case, it's very hard and time consuming, and I don't know if it's really efficient.
Anyway, I came back to HT by sight reading: it's easier, but to memorize, you have to play a lot of time, and repeat, repeat. When I felt that I wasn't confortable (especially with the LH), I came back to HS.
Then finished the 2 pieces with a slow play in order to respect the PPI. Then did the same with the 2 other pieces.
Less time to practise, I played the Invention #8 HT at 100% speed, making mistakes because I didn't master some passages, and also because memory is failing me. Mental play is very important, I should practise it when I'm not in front of the piano. And also repeat some passages with different speeds, HS or HT, depending on the mood. This allows exploration of the segments with different points of view, testing different gestures and techniques. Remember, you must come rapidly to 100% speed in order to work at a slower speed without bad habits. If you begin at a slow pace and stick to it too long, you take the risk to have different gestures and habits that you can't allow while playing at fast speed. Instead of learning bad habits, quickly come to speed HS and acquire the correct gestures with relaxed hands, fingers and arms.
Also worked Invention #1 HT at 70% speed.
I practised the Inventions #8 (nearly mastered), and #1 HT at 100% speed. And I started to play HS the Invention #13. Then I switched to Mozart and Schubert.
All the way, my mind wanted to practise hard the RH, especially in the Rondo of Schubert where you have to torture a little your little finger in the passage E4F#5E5 G#4A5G#5 B4C#6B5 E5F#6E6. I began to feel hot in the little finger, and I should have stopped sooner... I ended with the invention #13 at a slow speed HS. I was very tired, and my mind was... blank, I felt I was playing automatically, without thinking. I knew I was pushing too much, but I continued until the end.
Tuesday evening, I felt I pushed too much. I felt already on Monday a pain in the last finger of the RH, and it raised little by little up to my shoulder and back.
And that's because I failed to respect one of the most important rule (among many others...) of the method: relaxation! It's one of the utmost rule not to forget while playing, because it's the key to endurance of practise, and also the key to break the speed wall when encountered.
Today, I still feel the pain, and I think I have some kind of tendonitis due to the hard work. Today, I forced myself not to play the piano, since I also work with a computer: the fingers have to work too, it doesn't help the healing.
It's so hard not to play the piano that I practised the LH of the Impromptu (with the score) and the Rondo of Schubert (by heart, play the RH in my head in the same time). With relaxation in mind this time, realizing each time I was too tense, and that I had to go slower in order to get my fingers more relaxed. It's very hard to think about that while practising, it's like meditation you know: your thoughts are coming, coming, and you forget that you have to watch them, not follow them.
So the lesson is to be very careful of relaxation: relaxed fingers, hand, arms. And also, stop once you feel that you're pushing too much, and feel some pain. I felt pain in the back too, it was too stiff because of the long practise sitted in front of the instrument.
Have you also encountered this problem? What are your solutions? Feel free to comment and discuss about that!
PS: I raised the font size of the website, it is too hard to read. What do you think of the new font size?