Bach, J.S.: Well-Tempered Clavier II Fugue XXIII in B, BWV 892
It took months for me to bond with this fugue. It's technically very difficult, but the more daunting challenge was the interpretation.
For me, it came down to simplicity vs complexity. The primary subject is the simplest thing, a rising 3rd, a falling 3rd, and a rising 6th (inverted 3rd), outlining an authentic cadence (I-IV-V-I), the most basic of all. Rhythmically, it couldn't be straighter: 7 half notes, no rests, no syncopation. It's the music of kindergarten. Or "Do Re Me" from The Sound of Music. In stark contrast, underneath and between the primary subjects, Bach weaves a haunting fugal tapestry of remote tonalities and rich harmonies. I felt an aspect of reminiscence to this music. (This is, after all, the last great 4-voice fugue of the two books.) I wanted to hear two dimensions, one distant, as if overheard from another room, and the other clear and in the foreground.