In 1894 Johannes Brahms asked the clarinettist Richard Mühlfeld 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.