Here's how I conceptualize Brahms's Piano Concerto No. 1 in D minor:
At a concert hall in Hanover, Germany
January 22, 1859
Johannes Brahms, wearing a cutaway with tails, walked across the stage amid moderate applause. He seated himself confidently at the grand piano and brushed back his longish hair. Joseph Joachim stood at the podium with baton in hand while members of the orchestra finished their tunings and rustlings. The hall grew quiet.
This was Brahms's first public performance of his Piano Concerto No. 1 in D minor. Much struggle had brought this music from a failed symphonic effort to a new incarnation. Nothing could prevent its living in some form -- this was a memorial to his dear friend, Robert Schumann, who had died two and a half years ago.
Joachim glanced at Brahms and, when satisfied that the composer was ready, turned back to the orchestra. Raising both hands, he jerked them in mid-air to engage the timpani for an opening stroke of horn-shared foreboding. The strings entered on passionate and shivering peals, conjuring up a terrifying world of restless, venturing ghosts. Woodwinds trilled hysterically with trumpets stabbing their plaintive accents. The swirling elements boiled with intensity until...the flames subsided into an atmosphere of confused reverie. Uncertain memories rose on the intonations of dark oboes and wistful flutes. But remembrance was overcome by a flood of churning confusion, by strong currents of old manias -- of joy and terror -- sweeping through and inundating the Rhenish music. And then the flood abated, with orchestral pulses softening for the entrance of the soloist.
Tears of tone cascaded gently across the keyboard...but soon these tones strengthened into resurgent inflections of madness. The fingers of Brahms spoke to the spirit of his friend in a wordless language while the orchestra wove a strange circle of emotions around the piano's musings. Then quietude.
Brahms attacked the keys vigorously, filling the hall with emphatic evocations. In fits of runs and sudden stops, the piano declaimed the essence of the lost composer, as well as the depth of Brahms's regard. The self-possessed young man played with power, maintaining strong pulses of rhythm. His lack of perfect technique was adroitly managed -- the hands subtly filling in blocks of color, with a few missed notes inconsequential. Forces built and swelled into a passion of complex yearnings. Then a song with no words, a poised tune to accompany a god of art on his journey into realms of other being. The song transfigured into coarsening textures with orchestra and piano blending into unresolvable feelings. Paroxysms of grief flew from the keys, and the spiraling compressions of the orchestra led to the final moments of the first movement.
Here's a YouTube excerpt with Gilels, Jochum, and the Berlin Philharmonic