Study Chopin’s Polonaise in C-sharp minor, Op. 26 No. 1. Bar 49 closes the first section in C-sharp minor, its dominant, G sharp, resolving to the tonic; bar 50 goes on in D-flat major, which is C-sharp major renamed, and writes the G sharp as A flat. This is a respelling at a parallel-minor/major boundary, not one unchanged chord renamed: the tonic’s E becomes F. The card and keyboard task separately show how the same diminished-seventh chord can lead to different keys. At the keyboard: resolve one chord into two enharmonic keys.