The two-movement symphony was written in 1927/28. (A sketched third movement was rejected, as with Opp. 20 and 22).
As the title suggests, it again uses models of classical form. The first movement is laid out like a sonata movement; following the rules of the early Classical period, the exposition is repeated, followed by a development and a recapitulation. The second movement consists of seven variations plus coda over the retrograde of the basic row. As with the String Trio Op. 20, the sonata form of the first movement is not comprehensible for the listener. The exposition, characterised by two double canons in a sonorous register and mirrored around a medial axis, is followed by a dispersed development section and a recapitulation varied beyond recognition; the compact, deep sounds of the outset turn into delicate, disintegrating tones in the high register. The second half of every variation in the final movement is the precise retrograde of the first, like horizontal and vertical symmetries, greatly important for the piece – and for Webern’s late work in general; they are essential to the static impression of the piece. The composer also used an especially constructed row for the first time; the second half is the retrograde (transposed by a tritone) of the first. Thus, the symmetrical overall structure corresponds in a typical manner to the construction of the smallest elements; the form of the row becomes a specific principle, the germ of the large-scale form.