I mentioned yesterday in passing a difficult left-hand chord near the beginning of Chopin’s Mazurka in A minor, Op. 67 No. 4. The chord is, from the bottom upwards, E flat, A, C, F. Rearranging that into root position it runs F, A, C, E flat, so it is the dominant seventh in the key of B flat. Now the key of B flat (major or minor) is about as distant from the A minor key of the Mazurka as you can get, yet it still has two notes, A and C, in common with the tonic chord of the piece.
It is this sort of thing that goes, I think, part of the way to explaining Chopin’s attractiveness to the Western ear, especially the musically conservative one. Most of his melodies are, when shorn of their decorative twiddles, straightforwardly, comfortably, diatonic: you can hum along to them, although I wish you wouldn’t. But the harmonies he chooses to put under those melodies are often quite wildly adventurous. So, while being reassured by a pretty hummable tune, we can allow ourselves the delightful frisson of hearing exotic harmonies.
One finds a similar combination of simple tune and unexpected chords in Country and Western music.
I should perhaps add that I have a high regard for Chopin; all the higher since I have started to learn to play some of his easier pieces. Here, just in case anybody’s really interested, (and even if you’re not), is the first section, repeated with twiddles at the end, of that Mazurka: