Variations and Fugue on a Theme by Bach, Op. 81

When we hear "a theme by Bach" today, what first comes to mind might be the B-flat, A, C, B-natural (BACH) motif. This is because J. S. Bach himself frequently used it in his own works, and it is also famous for being used by many German Romantic composers, such as Schumann and Liszt, as an homage to him during the "Bach Revival" era from the 18th century onwards. Indeed, Reger himself wrote a large-scale organ work, Fantasia and Fugue on a Theme by Bach, Op. 46, using this motif. However, the B-flat, A, C, B-natural theme does not appear in this piano work. This is because the "Bach theme" in this work is derived from a specific work by J. S. Bach.

The impetus for this work's creation was a concert held in Munich on April 16, 1904. Satisfied with the great success of his works performed there, Reger offered to dedicate a new "large-scale piano work" to the pianist, Schmidt-Lindner. In response, Lindner proposed as the theme for the work the ritornello theme played by oboe d'amore and basso continuo in the fourth movement aria "God's omnipotence is unfathomable" from Johann Sebastian Bach's church cantata Auf Christi Himmelfahrt allein (BWV 128).

Approximately two months after this concert, Variations and Fugue on a Theme by Bach, Op. 81, was completed. It was then premiered on December 14 of the same year in Munich, naturally by Schmidt-Lindner on the piano.

This monumental work, consisting of 14 variations and a large-scale double fugue, is the most profound and expansive large-scale work among Reger's solo piano compositions. It is a set of variations characteristic of Reger, who ardently admired Bach, Beethoven, and Brahms, and prided himself on being a composer in their lineage, incorporating both German Baroque and Romantic elements. Throughout this piano work, one can perceive bold and rich sonorities reminiscent of his organ works, a technique evident in every corner of the music.

Theme: Andante

The instruction "like an oboe solo" at the beginning is, needless to say, given with the aforementioned aria from which the theme is quoted in mind. The 14-measure theme melody is presented with a weighty, smooth legato under strict harmonic progression.

Variation 1: L’istesso tempo

A variation where the theme melody and harmonic progression remain, but sixteenth-note movement is added to the inner voices. It begins p like the theme, but the latter half gradually expands in range, concluding with a weighty sound reminiscent of an organ.

Variation 2: Sempre espressivo ed assai legato

Similar to Variation 1, the inner voices are varied. The musical flow is largely unchanged from Variation 1, but the inner voice movement becomes sixteenth-note triplets, adding a flowing motion to the music.

Variation 3: Grave assai

This variation begins with an introductory section, which, in contrast to the preceding music, is characterized by chromatic progression and an expanded range. After a quiet p chromatic descent, the opening of the theme melody is played, followed by a sudden dynamic change and a rapid, improvisatory arpeggio of chords (m. 49). The opening of the theme melody then reappears but ends fragmentarily, and the piece concludes as if fading away at ppp, leaving its lingering resonance. Such extreme use of dynamics, changes in timbre, and chromatic techniques are frequently found in Reger's organ works and are characteristic of his music.

Variation 4: Vivace

This is a variation with active rhythms, centered on thirty-second notes. Unlike the organ-like Variation 3, it is filled with highly pianistic chromatic progressions. At first glance, the theme might seem absent from the score, but the melodic theme is firmly embedded within the intricate thirty-second notes. It is a brilliant piece of music, solidly based on the original theme and harmonic progression.

Variation 5: Vivace

Following Variation 4, this is another pianistic variation. Here, however, the theme melody is treated fragmentarily, with F, B-flat, C, D-flat, C, A, B-flat used as a single element around which the variation unfolds. It is a dazzling piece of music, characterized by repeated octaves on the same note played in thirty-second notes.

Variation 6: Allegro moderato

Beginning with a majestic sound of octaves in both hands, brilliant music unfolds throughout a wide range. While the opening of the theme melody is prominent in this variation, a free variation is achieved by thoroughly incorporating the theme melody element by element. Furthermore, the weighty low bass and the arpeggios faithful to the harmonic progression will likely recall the music of Brahms, whom Reger admired, rather than being solely Reger's unique technique.

Variation 7: Adagio

After a series of pianistic and brilliant variations, this variation once again begins with an introductory section. Throughout, the music proceeds with a quietness of pp or less, centered on ascending minor seconds, but gradually, fragments of the theme melody begin to appear (m. 121 onwards). Its conclusion clearly presents the ending of the theme melody, closing with chromatic triplet movement resonating in the lower voices.

Variation 8: Vivace

Again, a brilliant, improvisatory variation begins with a ff dynamic. Only the opening of the theme melody is treated in this variation; apart from its fragmentary and elemental use, there is no presentation of the full theme melody. While the key signature changes from B minor to C major, the music actually features dizzying modulations with a continuous succession of weighty chords and arpeggios of double stops. This music is abundantly filled with continuous ascending chords and double stops, a technique frequently used in Reger's organ works and characteristic of his music.

Variation 9: Grave e sempre molto espressivo

This variation is slow and spacious, as if taking a breath. The key changes to B major, and the opening of the theme is presented within a major key sonority. However, the music is supported not by the theme melody itself, but by the chromatic progression of triplets in the lower voices. The theme melody is played primarily in single notes at a very slow tempo, but the chords in the lower voices consistently dominate the music, creating a unique sound.

Variation 10: Poco vivace

This is the shortest variation among the 14. It lacks a clear theme presentation and is characterized by flowing octaves in the bass and chromatic progressions supported by them. Along with the following Variation 11, it is considered to have a strong interlude-like role.

Variation 11: Allegro agitato

This variation, the second shortest after Variation 10, is also considered to have a strong interlude-like role, including the absence of a theme presentation. However, the variation itself forms a pair with Variation 10. Unlike the flowing Variation 10, this is music with a pressing momentum and thickness.

Variation 12: Andante sostenuto

This variation also features a relatively free melody, supported by weighty harmonic progressions in the lower voices. However, the concluding part of the theme melody is finally used in the latter half (m. 211 onwards). Yet, this theme is not fully concluded either, but rather dissolves back into the weighty harmonic progression, ending with a major key sonority.

Variation 13: Vivace

This is a brilliant variation, played with a dazzling melody, retaining only slight elements of the theme melody. By returning to B minor in this variation, one might finally perceive the echoes of the theme in various parts of the music. To such an extent has the form of the theme melody itself disappeared, yet it remains consistently highly virtuosic, brilliant, and impressive music.

Variation 14: Con moto

This final variation continues the flow of Variation 13 while increasing in weightiness. Most notably, the theme melody is majestically played in octaves in the lowest register. The way the theme melody resounds solemnly, interspersed with short interludes, is like the pedal voice of an organ. Indeed, Reger invariably uses this very technique—that is, making the theme resound again in octaves in the pedal voice at the conclusion of a work—in his large-scale organ works (Chorale Fantasies). Under this characteristic Reger technique, the music reaches its climax, concluding with the greatest dynamics yet, without losing its momentum and volume.

Fugue: Sostenuto

Positioned as the epilogue of this work, the theme used in this fugue is entirely new and different from the preceding ones. It is a double fugue based on two themes: one appearing at the beginning (mm. 255–258) and another in the second part (mm. 333–336), and it is not the "Bach theme" used in Variations 1–14. However, these double fugue themes are not entirely unrelated new elements; they are derived from the opening motif of the 14th variation.

Reger is here, perhaps, intentionally chose to use a new element born within his own variations as the fugue theme, rather than the previous "Bach theme," to unify and conclude the entire work. Concluding a musical work with a lengthy fugue is a common practice in German music. However, from this large-scale set of variations, one can infer that Reger, while thoroughly incorporating this traditional technique, also sought and implemented his own originality within it.