Chopin left only a small number of works adopting the sonata form, the predominant form of the classical period: in addition to the piano trio of his early years, there are the two con-certos and the three piano sonatas as well that the late sonata op. 65 for cello. The two piano sonatas op. 35 and 58 are also among his most significant works.
The sonata in B flat minor was composed in 1839, when the funeral march which made it famous had already been published two years ago. By linking free and imposed form, passion and clarity, the work whose final movement is very singular - 75 measures of eighth-note triplets in cascades and in unison - testifies to an inimitable mastery.