Brahms, the mysterious

My faculty recital is coming up this coming Sunday. The program is:

Britten, Canticle III 

Brahms, Sonata in f minor, Opus 120, no 1

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Journey, Lori Laitman

Vocalise-Étude, Olivier Messiaen

Spanisches Liederspiel, Opus 74, Robert Schumann

What has been interesting is that: most of this program is "new" to me, meaning the first time performing it in public. The oldest piece on the program is a *very* old one. I've known it literally half my life: I first learned of its existence, and learned it musically, on clarinet as a high school student. In years following, I would learn it and play it many times with different clarinetists and violists (Brahms himself transcribed the piece for viola after the initial performances and publications).

Why is the oldest, most familiar piece (to me) still posing questions? 

Brahms would have still been working with a piano that isn't quite like the modern concert grand. I've had the immense privilege of playing a piano much like his 1867 Streicher. That sound wasn't quite as robust or resonant as what a pianist usually plays when either of the Opus 120 sonatas are programmed. 

The questions I'm still asking (these are in no particular order):

1. How can I still find more colors and be more imaginative with voicing?

2. Are there any places that I can still be using more rubato?

3. Why has he written some passage the way that he has? 

There is one passage in particular that perplexes me. It falls in the middle of the development, and Brahms is really "in the wrong key" - sharp minor v. (!) The rhythmic scancion, syncopation, series of tied notes and sequences, and pianistic difficulty - something was really "up" with him in this section. I'm trying to poke around and see if I can't find a copy of the autograph. What I'm wondering if this gave him as much compositional trouble as it gives interpreters and technicians. 

In the meantime, I will keep wondering, and keep practicing.