Frédéric Chopin Mazurka in B minor, Op. 33 No. 4 is one of the longest mazurkas at nearly 5 minutes in length. The piece is written in rondò form. The piece begins with a captivating main melody, decorated with grace notes and trills. This melody is repeated a total of eight times throughout the piece; between it, different melodies appear, but the main melody always returns.