Piano Concerto No. 23, K. 488, 1st Mvmt.

from: W. A. Mozart (1756-1791)

Originally in A major, transposed here to Bb. Includes option to play many of the (extremely delicious) tutti sections. If played on an old-pitch alto, it will sound at original pitch and can be accompanied (though this is far from ideal) by a Piano II (orchestral reduction) part. But as an étude played alone, I believe it's one of the best.