We encounter markings in printed music that are difficult to understand, ranging from notes that are marked as if to be played staccato but with a slur over them, to peculiar tempo indications, like rubato. I don't recall where I found out that those slurred staccato notes indicate a very specific touch on the piano.
But yesterday I was overjoyed to find them in Beethoven's "Spring" Sonata, which I am exploring with Gregor Kitzis, violin. Four repeated unisons, in both instruments, once marked crescendo, at other times with no crescendo indicated.
If played correctly there will be no pedal used, but rather a touch
that permits the hammers to restrike the strings without the dampers
reducing the vibrations in between hammer strokes. The result is a very
specific overtone ring that can be attained only in this fashion.
Gregor had to move so that he could savor the result and savor he did.
I
think this is the reason why these sonatas are for piano and violin,
not the other way around: their acoustical world is generated by the
sympathetic vibration of the piano strings.