I always thought it meant the notes are to be played together, assuming that since there are two voices and both notes have accidentals they end up too separated, so the bracket is used to show they're played at the same time; but my teacher insisted Chopin wouldn't use a disonance like that (even though there are minor seconds in other of his works) and told me to play one note after the other.
but my teacher insisted Chopin wouldn't use a disonance like that (even though there are minor seconds in other of his works) and told me to play one note after the other.
Wait, let me cry. They ARE played at the same time. Change teacher, now. This is imperative.