Of the thirteen pieces of exquisite Bach known to us as the “Musical Offering”, the Fugue has the most substance; if we leave out the comparatively large-scale Trio sonata it is also the most extensive. It has first and foremost the theme in common with the other pieces (mostly canons), that “right royal theme” which Bach in the dedication attributed to the dedicatee Frederick the Great, referring to it as the “noblest part” of the Offering. However, the grandeur and distinction of the theme and the power of the expression reveal the unmistakable stamp of Bach's greatness, and it is more likely that this resulted from the “more elaborate revision” which the old master felt was necessary after his visit to the King, than that the King, on requesting the improvisation of a six-part fugue, was capable of promptly producing such a royal idea as this.
Webern's transcription of the Bach Fugue is not, for all its individuality of conception, a late contribution to the art of musical transformation. This must be made expressly clear, as it can easily be taken for such and for this reason was often the object of heated dispute. On the other hand it is manifest that Webern did not have in mind a faithful adaptation along the lines of a purist evocation of style. Similarly there is no doubt about the integrity of his purpose. As he states clearly in a letter to Hermann Scherchen, printed many times since its first publication (1955), what he wanted was: to bring the music out of its esoteric, abstract presentation and make it alive and comprehensible, to bring it closer to the listener. “My orchestration attempts … to reveal the interrelation of motifs. This was not always easy. It seeks of course in addition to show how I see the character of the work.” Webern knew that this was “a risky enterprise” in so far as his interpretation took the Fugue out of the spiritual and emotional world of its creator. Such a risk is doubtless also involved in any performance on the piano. With the orchestration the difference is only one of degree. It multiplies the possibilities of estrangement from the original.
Webern did not sidestep the danger. On the contrary, he faced it squarely. What must be considered as interpretation in his version of the Fugue is very much imbued with subjective elements; this can be noted even in the visual effect of the notation in the score. The fact that he insisted on calling it “his” Bach Fugue whenever it was spoken of may serve as an indication that he was well aware of its character as an independent creation based on Bach. In actual fact there is a notable similarity between the two composers in the essentials of artistic representation, in the casuistic strictness of concept and in the manner of expression. Also the intrinsic energy of the latter is, with both, often linked with the tension inherent in the structural relationships. In the Bach Fugue Webern has tried to release this energy for concrete effect, mainly through changes of tempo which are meant to show up the formal structure. This already occurs in the setting out of the eight-bar theme, where the chromatic motion of the middle section between the last crotchet of the third bar and the first crotchet of the seventh takes on an added refinement with the ”poco rubato”. When Webern separated almost every descending minor second from the following one by means of phrasing and articulation, as well as the changing timbre of three alternating instruments, as if they were isolated sighs, he came in his interpretation remarkably close to the romantic weltschmerz-chromaticism characteristic of, say, Mahler, and of his own generation. The deviation is especially obvious in the extensive intermezzi (bars 57 to 94) and before the final return of the theme (192 to 196), since the chromatic motif-fragments accumulate here for purposes of contrast. The interrelation of motifs is impossible to miss.
As with the final build-up of latent energy (193 ff.), owing to the structural tension the caesura-effect of certain interruptions of the form, combined with the qualities of expression, is also increased at other exposed points in the work (cf. the boundaries of the episodes in bars 57 and 78 and before). Here it can be seen that the whole formal process has the same basic model as the theme in each of its twelve phases. Nevertheless, the total structure which stretches across the whole work is considerably impeded by the motley diversity of motif-relationships, which stand out as the smallest units in the kaleidoscopic sound-picture of the Webern orchestra. Possibly Webern did succeed in achieving a rounded performance, when he himself rehearsed and conducted the work. We have no proof either way. The first performance was in London on 25 April 1935, with Webern conducting. He had finished the instrumentation not long before. This work had occupied him from the beginning of December 1934 until the beginning of February 1935, the same length of time it took Bach to write the whole of his Ars canonica (7 May to 7 July 1747).