I was originally enlightened about the value of blocking out intricate and tricky passages when I attended a rehearsal of Rudolf Serkin and the New York Philharmonic.
He was about to play the Beethoven “Emperor” Concerto No. 5 with its majestic opener of broken chords (arpeggios) and as a warm-up, he silently blocked out a series of chords numerous times.
At this moment in time (easily 35 years ago) I was beginning to explore the same avenue of practicing, (though audibly) and after observing a virtuoso break down the ingredients of a monumental passage into “chunks” I permanently joined the ranks of pianists who regularly embraced this learning approach. (of course, it was combined with many others)
Here’s an example where I navigate a tricky section of Beethoven’s “Pathetique” Sonata, No. 8, Op. 13.
Naturally, it’s not enough to chunk aimlessly. In this case, the harmonic rhythm, or progression of harmony frames practicing. Knowing about key modulations, voicing, and having a workable fingering are part of the intricate learning landscape. Intertwined is the physical approach–how the wrist and arm work together in mobilizing energies to the fingers.
MORE Blocking as I practice the “Pathetique” first movement,(starting measure–27) Add in rhythms, dotted-eighth/16ths applications and the reverse (16th-dotted-eighth) plus thumb placements. (I rehearse where my thumb is advancing through a passage, and isolate those spots) I think of my thumb as a hand “guide” over the keyboard.