WTC I/21 in Bb major - Prelude

    from Siglind Bruhn
J.S. Bach's Well-Tempered Clavier
In-depth Analysis and Interpretation

I/21.1.1 The prelude-type

The Bb major prelude is essentially non-polyphonic in texture. The performer's two hands act either in alternating patterns or join forces for multiple-voiced chords. Never does one of them establish a pattern without the other.

There are three conspicuous figures. Two of them are characterized by an aspect of keyboard technique rather than by particular melodic or rhythmic shapes. The first figure appears as a pattern of open-position broken chords, to be executed in a complementary play between the two hands. This figure prevails in bars 1-7 and 9, after which it recurs only in bar 21. The second figure appears as a single-voiced wavy run, to be played also in virtuoso style, i.e. in the performer's own choice of complementary use of the two hands. This figure is introduced in bars 3/4 and taken up in bar 8; in bars 10-20 it occurs interspersed with the third figure. The last component, in contrast to the two one-track figures described before, employs both hands simultaneously, creating a dotted-note chordal pattern (see bars 11, 13, 15 and, in modified rhythm, bars 17/18).

The composition thus recalls several Baroque genres: the toccata, the fantasy and the French overture. As there are no real melodic features and, except for the short dotted-note figures, no prominent rhythms, the aspects which solely characterize the piece are, on the one hand, the virtuoso layout, on the other hand, the harmonic progressions and the sequential patterns within it.


I/21.1.2 The overall design of the prelude

The first harmonic progression concludes in the first half of bar 3, with the perfect cadence in the home key Bb major. However, while this Bb major chord certainly brings the harmonic resolution to the preceding F7 chord, the pitch position of the bass with its leap of one and a half octaves (see bar 3d) counteracts any true relaxation and designates the downbeat of bar 3 as the beginning of a new structural unit.

The second harmonic progression is more extended. It modulates to the dominant F major which first appears by way of a plagal cadence, in bars 5m-6m. The seventh Eb, however, added at the last moment, converts the F major chord into a V7 and thus once more refers back to Bb major.

The dominant key is only firmly established with the authentic cadence which concludes, complete with a traditional cadential-bass pattern, on the downbeat of bar 10 (with a possible extension throughout the broken F major, see the first half of bar 10). This cadential close should by all means be regarded as a structural caesura. Understanding this is particularly important since the virtuoso thirty-second-note pattern continues uninterrupted. It therefore happens easily that the structural partition is either overlooked or misplaced - e.g. after the D on the downbeat of bar 11 which, however, already represents the first step into the subsequent harmonic and structural unit.

The prelude thus contains only two structural sections:

I bars 1 - 10 tonic - dominant
II bars 10 - 21 dominant - tonic


I/21.1.3 Practical considerations for performers

Both the very regular rhythmic structure with almost continuous thirty-second-note motion and the broken-chord patterns indicate a rather lively basic character. As for the tempo, this virtuoso piece should give a very brilliant impression and may be played almost as fast as is technically possible. (What is swift and brilliant, however, is the surface pattern, while the actual pulse of the piece - the eighth-notes - are not really all that fast.)

Whether this tempo and character are valid throughout the entire prelude is a question which is frequently being discussed. In one of the manuscripts, the introduction of the dotted-note rhythm pattern in bar 11 is marked Adagio. What are we to think of the fact that this indication did obviously not form part of the original layout but was added later? One possible interpretation is that Bach could have decided to add this heading on the spur of the moment because a performer (student?) played in a character which he deemed too light to be appropriate; in this case the indication may refer to a contrast in touch and expressivity rather than to any considerable change of tempo. Or, basically along the same lines, even if Bach originally estimated that an intended change of character was expressed clearly enough by the rhythmic hint at the style of the French overture and did not need any explicit verbal invitation, he may have added Adagio to suggest a freer treatment of tempo - rubato. (The two extreme interpretations, either to play through the entire piece without any change of attitude, or to play the second half twice as slowly as the first, are certainly the least likely solutions.)

The appropriate articulation includes non legato for the eighth-notes and quasi legato for the thirty-second-notes. Touch should vary with the character of the components: lightly bouncing non legato combined with a very crisp quasi legato in bars 1-10 and 19/20, heavier detached style (possibly combined with a denser legato) in bars 11-18.

The only ornament occurring in this piece poses a problem. The downbeat in bar 19 carries a compound ornament which, in correct execution, encompasses eight notes and ends in a tie-prolongation, a feature not at all easy to realize in the speed of this prelude. (In fact it is close to impossible if the tempo is as brilliant as would be desirable for the first half, and not modified drastically in the French-overture section.)

(ex. 26)


I/21.1.4 What is happening in this prelude

Three aspects account for the chief processes in this prelude: the use of the three figures (see above under I/21.1.1), the harmonic progressions (see above under I/21.1.2), and several sequential patterns in simple descending and ascending lines.

The first phrase is determined entirely by figure 1. It appears in a pattern of descending half-bar sequences (bars 1/2), rounded off by a free continuation which leads to a half cadence. The descending sequences are counter-balanced in the following phrase where the combinations of figures 1 and 2 (bar 3) trigger two ascending sequences, one complete and one varied and extended (see bars 4 and 5-6m). This ending, just like that of the first phrase, represents again an F7 chord whose resolution (on the middle beat of bar 6), instead of passively concluding the preceding process, embarks on a new one.

The third phrase picks up the ascending motion, from Bb through an entire octave to A, commencing in straightforward chromatic steps and continuing in a diatonic passage with octave displacements (see bars 6m-8). While the ascent presents itself in figure 1 pattern, figure 2 in bar 8 returns in a double curve to the low E, the leading-note of the long prepared dominant. A one-bar cadential pattern with figure 1 confirms this key and with it the first half of the prelude.

In bar 10 Bach very subtly creates the impression of both rounding off and, at the same time, announcing something new. While the first half of the prelude had been made up entirely of the two figures with open-position broken chords and scalar runs, the tail of its final cadence introduces a combination of the two figures: a pattern which, like figure 2, uses clear one-track texture but, like figure 1, moves in broken chords. This combination (here referred to as figure 1+2), turns out to frame the second half of the piece.

Bar 11 presents the first statement of the dotted-note figure 3. This is linked to its two descending sequences by extensive statements of figure 2 whose dive and soar respectively span almost three octaves. (Despite the inverted direction of the run in the second statement of figure, the listener can still perceive the continuing sequential pattern as shown in ex. 104 below.) After the second sequence, the recurrence of figure 1+2 seems to announce the pending close of this section. The cadence in the home key (see bars 17/18) is, however, diverted by the seventh added to the tonic chord (see bar 18d - the same process as earlier in bars 5/6), and another statement of figure 1+2 is needed. After the compound ornament - which can thus be taken to represent the structural completion of the second section (though not its harmonic close) - one bar each of figure 2 and figure 1 complete the larger frame of the prelude and thus bring the piece to an end which appears well-balanced with regard to the material of the entire prelude.

The dynamic processes in the prelude are very straightforward as they follow almost literally the sequential ascents and descents. The following simplified version of the Bb major prelude attempts to facilitate the understanding of the structure by exposing the basic lines only, together with the dynamic processes they trigger (ex. 27)



WTC I/21 in Bb major -- Fugue

I/21.2.1 The subject

The subject begins after one eighth-note rest, extends through four entire bars and ends on the downbeat of bar 5, where the D represents the return to the tonic after the F7 chord in bar 4 beats 2 and 3. (More on this later.)

A closer look at the phrase structure of the subject reveals three subphrases. These are easily distinguishable once the sequential pattern is recognized - behind its veil of ornamentation:

compare the initial subphrase F-G-F-Bb-D-C
with its sequence one tone higher G-A-G-C-Eb-D (from A-G-Bb-A-G-F)
and with the next, a fourth higher Bb-C-Bb-Eb-D
Bb-A-Bb-Eb-D (from Bb-C-A-Bb-C-D-Eb)

Phrasing within the subject therefore occurs after the downbeats of bars 2 and 3 respectively, with exactly one bar length for each of the two subphrases), while the subsequent two bars had best not be further structured.

The interval organization in this subject includes sixths, fourths and seconds in the eighth-notes and predominantly small intervals in the sixteenth-notes; that these sixteenth-notes are essentially ornamental in character was already demonstrated above. As the sixths occur in weak metrical positions (i.e. after the beat, not towards it), these large leaps are not perceived as communicating emotional tension, but rather as the expression of an energetically bouncing temperament. Corresponding with this lively interval pattern, the rhythmic pattern throughout the fugue is very simple, consisting almost exclusively of eighth-notes and sixteenth-notes - even the regular syncopations in the main contrapuntal voice (see U: bars 5-7 etc.) cannot diminish this effect.

The harmonic background of the subject is characterized by two active steps within the first two subphrases: both times a simpler chord, which underlies the five-eighth-note upbeat, is followed by an incomplete minor-seventh chord. The third bar concludes the cadence with a straightforward V7-I. Thus, as far as the harmonic progression is concerned, the subject already closes on the downbeat of bar 4. In this fugue, however, Bach seems determined to create a dance-like character and thus prefers phrases with even numbers of bars. The fourth bar, consisting of an exact repetition of the third, thus appears as a metric complement with neither melodic nor harmonic "information" of its own.

(ex. 28)

The dynamic design of the subject should convey the phrase structure, the metric organization as well as the harmonic features. A distinctly virtuoso aspect enters with the ascending sequences and their growing amount of embellishment.

Within the first two subphrases, the climax falls on the respective downbeats - both because this is the point of harmonic emphasis and because any other accent would blur the metric structure. (If the peak notes Bb and C are accented, a rendition easily resulting for simple lack of attention, this will necessarily give the listeners the mistaken impression that the subject begins with three upbeat eighth-notes followed by the first downbeat on Bb.)

By the time the third subphrase is approached, the meter is firmly established. Therefore, the fact that this incomplete sequence comes without what was previously the climax and instead just relaxes from the Eb (V7, bar 33) to the final D (I, bar 5d), insinuates that in this subphrase, highest pitch and dynamic peak coincide.

With regard to the relation between the three subphrase climaxes C, D and Eb, the virtuoso character of the piece supports the high Eb. (In case, however, a performer prefers an interpretation which seeks for more serious nuances in this fugue and its subject, it is also possible to regard the downbeat of bar 3 as the strongest climax and the two final bars as a less intense tail to the more substantial main body.)


I/21.2.2 The statements of the subject

This fugue contains only eight complete subject entries as well as an incomplete one.

1. bars 1 - 5 U 5. bars 22 - 26 M
2. bars 5 - 9 M 6. bars 26 - 30 L
3. bars 9 - 13 L
bars 35 - 37 M)
4. bars 13 - 17 U 8. bars 37 - 41 U
      9. bars 41 - 45 M

(ex. 29)

Except for the interval adjustment in the tonal answer, the subject remains untouched in detail as well as in shape throughout the fugue. No stretto or parallel statement ever materializes.


I/21.2.3 The counter-subjects

Ever after its first appearance, the subject comes escorted by companions which remain faithful throughout the work. They are, however, not quite as independent from their leader as true contrapuntal technique might desire, particularly in the case of the second companion which runs largely in parallels to the subject. Although the term "counter-subject" might thus not seem appropriate in its strictest sense, the usual abbreviations are employed here for easier reference.

CS1 is introduced in U: bars 5-9. Its three subphrases coincide exactly with those of the subject. As in the subject, the first and second subphrases are remotely related by ascending sequence (although it is the first subphrase which appears more elaborate than the second here). Also as in the subject, the third subphrase consists of a one-bar model followed by its repetition. (This subphrase even contains a four-note parallel to the subject; see e.g. bar 8 beat 1.)

As for the dynamic outline within this companion, the three climaxes fall slightly earlier than those in the subject. The prominent features within the first two subphrases are the final syncopations which certainly appear as the peak of tension. In the third subphrase, the short upbeat-like ascent which precedes the protracted note repetition seems to indicate a soft crescendo, followed by a long diminuendo.

CS2 seems more like a filler than a polyphonic partner (see e.g. U: bars 9-13). It consists of four short gestures interrupted by rests. The first two, again conceived as ascending sequences, complement the two sixteenth-notes missing in the rhythmic pattern established by the subject and CS1; their second note falls in perfect unison with the other companion, and their final eighth-note, rather than fulfilling any melodic purpose, complements the downbeat harmonies. The (identical) third and fourth figures blatantly double segments of the subject in parallel sixths. To look for a meaningful development of musical tension within this highly dependent element would mean to overrate its importance.

The following sketch shows the phrase structure and dynamic design (ex. 30):



I/21.2.4 The episodes

The Bb major fugue contains only three subject-free passages.

E1 bars 17 - 22 E2 bars 30 - 35 E3 bars 45 - 48

All of them are directly related to the primary material and can be divided into only two patterns, both of which are established in E1.

pattern a In bars 17-19, the third subphrase of the subject is sequenced one tone higher, while those of the two companions are imitated, i.e. sequenced in inverted voices, up one second or one ninth respectively. A very similar process can be observed in bars 45-47. Here the middle voice repeats the second half of the previous subject entry an octave lower, while the second half of CS1 moves from upper to lower voice (and thus two octaves down) and that of CS2 from lower to upper voice (one octave up).
pattern b In bars 19-22, E1 is reduced to two-part texture, and the material employed derives entirely from the subject. The upper voice continues in sequences of the bar-3 pattern (now descending by steps), while the lower voice takes up the first subphrase in inversion (compare L: bar 19 with U: bar 1) which is then also sequenced in descending steps. This combination recurs twice very similarly in E2. Bars 30-33 feature the inverted subject head in the upper voice (the descending sequences are underpinned only at their very ends by doubling in the middle voice), and the lower voice recalls the descending sequences of the bar-3 pattern. Bars 33-35 continue this process in inverted voices, the only difference being that the filling voice is now more complete (see L: bars 33-35).

The only episode bars which remain are the two cadential bars at the end of the composition. These feature a cadential-bass pattern and a traditional closing-formula in the upper voice.

As all these passages are designed in sequential patterns, the ascending or descending direction of each sequence determines the dynamic trend and, with it, the role each episode plays in the course of the fugue. Thus E1 momentarily surpasses the tension expressed in the fourth subject entry of bars 13-17 but consequently recedes with each bar; E2 is conceived, despite its two-fold structure, as a single decreasing line, and the first segment of E3 resembles an echo from which the cadential close resurfaces.

To sum up all that has been observed with regard to the subject's companions and the episode material, one can state that this fugue is only rudimentarily contrapuntal in texture and entirely determined by its subject. At the same time, it was noticed that the subject remains virtually unmodified throughout the composition. One might conclude that, in this fugue, it is not the material which matters, and that the chief task fulfilled here by the subject is to establish the vigor and mood upon which the entire piece will depend.


I/21.2.5 Character, tempo, articulation, ornament realization

The basic character of this fugue is, no doubt, rather lively. This interpretation is supported both by the simple rhythmic structure and by the pitch pattern which includes, as we saw, frequent leaps as well as ornamental sixteenth-notes.

The tempo may be very swift, particularly since the demands of polyphonic playing - and hearing - in this fugue are almost negligible. The corresponding articulation includes an energetically bouncing non legato for the eighth-notes and a crisp quasi legato for the sixteenth-notes. Ornaments do not occur in this fugue.

The relative tempo of the prelude to the fugue uses the larger pulse for a proportion:

one half-note (= 2 bars)
corresponds with
one dotted half-note (= 1/2 bar)
in the prelude
in the fugue

(Approximate metronome settings: prelude beats 72, fugue beats 108.)


I/21.2.6 The design of the fugue

As all subject statements are surrounded by the same two companions, looking to the primary material or the texture for guidance will not bring any results. In the absence of any conspicuous cadential patterns, an analysis of the structure must therefore rely on the episodes - which, as was observed, are also very simple in material and organization - and the harmonic development. On these two grounds, however, the structural layout of this fugue appears very clear and straightforward.

It has been shown above that the three episodes in this fugue relate to one another in such a way that E1 (with patterns a and b) recurs - split into its two halves - in E2 (pattern b) and E3 (pattern a). This may be interpreted as suggesting an axis symmetry (a+b --- b, a) and can thus hint at a design in which the first section would find its correspondence in the joined second and third sections.

The tonal organization of the piece supports this view. The four initial subject entries remain in the sphere of Bb major, with entries alternating on tonic and dominant. The first episode then modulates via the relative key G minor (pattern a) to its dominant D Major (pattern b). The fifth and sixth subject statements consequently represent the relative minor sphere (with G minor in bars 22-26 and C minor, the relative to the subdominant, in bars 26-30). The ensuing episode confirms the key of C minor. After this, the incomplete subject entry leads back to the major realm, so that the next complete statement can enter in the subdominant Eb major, followed by the return to the tonic in the final statement.

For a sketch showing the design of the fugue in Bb major see ex. 31.



I/21.2.7 The development of tension

A big dramatic development is clearly not the purpose of this virtuoso fugue. Once the subject with its two companions have been established, there is little distinction between successive entries. Interpretation of tension will thus have to concentrate on two features: the differentiation of color between the two major (outer) and the minor (middle) sections, and the gesture expressed in the episodes.

The course of the fugue will then show roughly the following picture.

Within the first four subject statements, the tension grows due to the growth in the number of voices, but without particular increase of emotional involvement. The first episode sets out with an ascending sequence which transitorily overshoots the fourth statement. Pattern b, by contrast, follows with descending sequences and the confirmation of the minor key, thus causing a slight dynamic decay which closes the first section.
The second section begins in softer tone color (differing not only in volume but also in terms of the intensity expressed in the non legato articulation). The episode which closes this section contains five bars of descending sequences, thus bringing the tension down to the lowest level in the fugue.
The incomplete statement which prompts the third section quickly reverts this process, both by returning to the major-key realm and by extending, as it were, the tension-increasing first half of the subject to altogether four bars. One thus finds the two major-key entries in the third section on a dynamic level comparable to that attained in the middle of the first section. The final episode, while resuming pattern a, uses it in much a different way: the upper and middle voices appear considerably lowered in pitch, thus producing an effect almost like that of octave displacement; and the connection between statement-tail and episode is not that of a sequence but that of a repeat in inverted voices (one could say that the pitch development seems as if paralyzed), thus adding to the effect of energy depletion.

The final cadence manages, chiefly by means of its prominent large leap in the upper voice, to regain some of the tension and conclude the fugue in an confident mood.