Brahms, waltz op. 39 no. 15 in A major.
First of all, Brahms op. 39 no. 15 is in A-flat major and besides it's a solo piece. Maybe you had a different one in mind?
PS: I know about the simplified version by Brahms, which is in A major, but that one is also a solo piece.
My goodness, why isn't it possible to post a tiny suggestion on PW without anybody erroneously claiming I am clueless. You should have read up on the topic before playing the know-it-all. No, you are wrong and not me! Brahms wrote the waltzes op. 39 originally for 4 hands (compare Wikipedia), and the original version of #15 is definitely in A major and not A-flat. Nor is this a solo piece. Brahms then transcribed his waltzes for 2 hands in two versions (one more difficult, the other simplified), and there he changed the key of the non-simplified version of #15 to A-flat. The 3 versions were published at the same time.
Brahms arranged all the waltzes for piano duet(not sure if the solo or duet version was the original version) and the duet version of No. 15 is in A major.
No, the other way round, see above. The duet version is the original version.
OTOH this piece does not, I think, fit the OP's request because the parts are of equal difficulty and neither part is advanced.
Yes, you are right here, I did not read the OP's request carefully. Sorry.
