I looked at the sheet music of the Military Polonaise by Chopin that I have. I saw something which looks more difficult than even the fast speed or the octaves. I saw a descending trill. I have never seen anything like it though I have heard it in Beethoven's 3rd piano concerto(the descending trill).
That last trill(or set of trills) on that page in the D major section is descending. There are a few octave trills before that but I assume I would be doing 1 trill in each hand and in contrary motion(so 1 trill starts on the principal note and the other and octave above starts on the auxiliary note). In my sheet music, that descending set of trills is written as just a single trill symbol over 5 descending notes. I bet I would have to use my 4th and 5th fingers for the beginning of the trill. But I can't trill well with those fingers. I could do a 4 measure long trill with my 2nd and 3rd fingers but my 4th and 5th fingers, I am lucky if I can trill for 1 measure evenly, normally I can only have 1 beat of it be even and my trill slows down as my 4th and 5th fingers get tired.
I have played some difficult Bach pieces that require me to do that 45 fingering for the trill so that I can reach down to about an octave away from the trill with my 1st, 2nd, and 3rd fingers and I still can't do it evenly. I don't know if I should try to learn this piece given that it has that descending trill. And how would I even play such a trill? Starting on the auxiliary note for the first trill and then the principal note for all the trills after that?