In 1894 Johannes Brahms asked the clarinettist Richard Muhlfeld to visit him during his beloved summer sojourn in Ischl, adding “It would be really wonderful if you brought your B flat clarinet with you, and if you were in no great hurry” for the two Sonatas op. 120 were waiting to be rehearsed. The first performances were given privately directly afterwards and the press enthusiastically reported: “The sonatas [...] are wonderful and will cause a great sensation.” Our edition of this work, today part of the clarinettist’s core repertoire, continues the revision of Brahms’s Duo Sonatas following the text in the new Brahms Complete Edition.