The sonatas stem from a period late in Brahms's life where he discovered the beauty of the sound and tonal colour of the clarinet.

[2] These were the last chamber pieces Brahms wrote before his death and are considered two of the great masterpieces in the clarinet repertoire.

Brahms also produced a frequently performed transcription of these works for viola with alterations to better suit the instrument.

In January 1891 he made a trip to Meiningen for an arts festival and was captivated by performances of Carl Maria von Weber's Clarinet Concerto No.

The solo clarinetist was Richard Mühlfeld, and Brahms began a fond friendship with the man whom he so admired.

The beautiful tone of “Fräulein Klarinette”[3] (as Brahms would nickname Mühlfeld) inspired him to begin composing again less than a year after he retired.

He wrote to Mühlfeld on August 26, inviting him to Bad Ischl, to perform them, stating cryptically that "it would be splendid if you brought your B♭ clarinet."

As Mühlfeld had other commitments that summer, he delayed responding, but went to Vienna in September to meet Brahms and to acquaint himself with the two sonatas.

It begins with a solo piano introduction in three parallel octaves, outlining a recurring motif throughout the movement.

Brahms did not reduce the scope of the piano part to accommodate for the clarinet, but created a more equal and harmonious relationship between soloist and pianist.

The piano plays with staggered hand entrances and joins the clarinet in recalling the second bar of the introduction.

A subito forte evokes the second theme combined with staggered entrances from both piano hands and clarinet.

A short interlude of sixteenth notes in the piano alludes to the B section and a final iteration of the melody ends the movement.

The movement begins with three accented Fs in a piano introduction serving as a sort of call to identify the first theme.