B-flat Minor P&F

Each book of the Well-Tempered Clavier features one fugue that is just monstrous. In Book One, it’s the final fugue — B Minor. That fugue has a long, extremely chromatic subject that encapsulates all twelve tones of the chromatic scale. This use of the entire chromatic scale as the subject out of which the entire piece is generated is a notable foreshadowing of the compositional system Schoenberg would eventually develop as the 12-tone system. In Book Two, it’s this one.

These two fugues have a lot in common: long (both in terms of subject length and total length), rhythmic, and extremely chromatic. While the Book One: B Minor fugue offers glimpses at where modern composers will eventually take the Western tonal system, the Book Two: B-flat Minor fugue is more retrospective. In this piece, Bach takes an incredibly difficult subject and proceeds to treat it with every possible advanced contrapuntal technique. 

The prelude, on the surface, couldn’t be more different than its partner. It’s gorgeous, with flowing, undulating lines that soothe as they glide across the keyboard. It’s a complete contrast to the sharpness and angularity of the fugue. Still, these two pieces are sneakily musically related in that the final melodic material we hear in the prelude comes directly out of the subject in the fugue. 

The Prelude

Curiously, it’s not just the fugue that is related to the first book of the WTC. There is an extremely close relationship between the B-flat Minor prelude in Book One and the B-flat Minor prelude here in Book Two. This prelude is more extended and contains more musical ideas, but its second and most prominent musical idea is identical to the main motif in the Book One prelude. 

The beginning of B-flat Minor Prelude, Book 1


The beginning of B-flat Minor Prelude, Book 2

Both preludes feature the same rhythmic and melodic pattern: short-short-long-long-long, with the short notes passing through an ascending gesture before landing on longer, repeated notes. (As an interesting aside, I’ve also heard this same musical gesture in at least one other minor piece by Bach that I unfortunately cannot specifically recall beyond that it was something orchestral.) There’s something about B-flat Minor that made Bach keep circling back to this particular musical idea.  


The complexity of the counterpoint is the other notable trait of this prelude. Written consistently in three-part counterpoint, it’s as dense as many of the fugues we’ve encountered up to this point (although not nearly as complex as the upcoming fugue, which is gangbusters). In some ways, it’s almost tempting to classify this work as a mislabeled fugue, but I don’t think that’s completely accurate. There are enough discrepancies that I’d stick my flag in the “contrapuntal, not fugal” side of the debate, although that line does get pretty thin at times. 

Here’s my reasoning: 

  • We start out with two voices straightaway. 
  • While two of our voices are introduced in rapid succession, the bass doesn’t get a crack at the ‘subject’ (for lack of a better word) until after we’ve had a fairly extended ‘episode.’

Nevertheless, we are eventually treated to the ‘subject’ in all three voices, and that distinctive short-short-long-long-long melodic line appears constantly, often in a quasi-stretto with other lines. Because this prelude is fairly long, Bach takes the opportunity to wander through an impressive array of harmonic areas. Like in a fugue, we return for a final iteration of the ‘subject’ in the tonic key, which leads us into an extended coda

This coda plays an atypically important structural role, linking us to the fugue that’s right around the corner. We begin with an steadily undulating, generally ascending scale in the bass (reminiscent of the B Minor prelude from Book One which features a walking bassline), with the soprano and alto in a descending sequence, call-and-responding to each other. Then, once we bottom out of the sequence, we start climbing — four notes up the scale, down a third, repeat. This happens first with the soprano and alto in sixths, and then again in thirds. 

Prelude. Four notes ascend, then jump a third. I only circled one iteration because it seemed confusing to do more. First we are in thirds, then we are in sixths (which functionally helps us move out of the sequence).

This musical idea of an ascending scale and then a falling third is exactly replicated in the subject of the fugue. 

Fugue subject. The exact same idea from the prelude reappears toward the end of the subject. 

While the character remains calm and soothing, this material helps bridge the gap between where we are and where we’re going. The use of thirds is also interesting, as thirds play an extremely prominent role at the end of the fugue. 

The Fugue 

This fugue is a beast, one of the most contrapuntally and technically complex fugues in the WTC II. We need to veer into a more theoretical arena to really grasp the scale of what Bach managed to achieve. 

To begin, let’s discuss the anatomy of the subject: it’s long, rhythmic, and rests make up an essential component. The image that always comes to mind is someone trying to claw their way out of something. 

Our subject: notice the stepwise motion, use of accidentals, and strategic use of rests.

It’s a four voice fugue with the alto going first, followed by the soprano, and then (curiously) by the bass. The bass introduction is often a notably thrilling moment; it’s frequently the final addition that provides us clear harmonic underpinnings. Here, the introduction of the bass is not undramatic, and it does fulfill its function of providing us some solid (albeit chromatic) harmonic ground. This grounding creates a sense that we could conceivably move on and experience a complex three-voice fugue. But we don’t — Bach dramatically completes the introduction of our voices with the tenor. Already in a quagmire, the tenor squeezes itself in and asserts its iteration of the subject. This is the moment I find most compelling in the exposition. There’s already a mind-bending amount of material in play (forgive the pun) and Bach tosses yet another ball in the air (and the mixed metaphor). 

After the final statement of the subject, we follow convention and move into our first episode. The intensity mellows, and we hear a thinner, lighter texture and take a brief detour into some major harmonies. The only bummer about this part is that my hands are slightly too small for it. I rarely run into this particular issue with Bach (as opposed to with someone like Rachmaninov, who famously had big hands). His idiom doesn’t call for huge chords, gigantic leaps, or extreme use of registers. On the occasion where there is a large interval to span, it’s usually possible to redistribute notes between the hands to grab everything. This particular phrase did have some uncomfortably large intervals. Most of them were able to be redistributed between the hands. However — there was one note that was such a pain to grab with my left hand, but was too far for my right to reach…I just left it out.

Nice, friendly-sounding episode; that note totally didn’t happen. (Shhh, don’t tell.) 

After this brief reprieve, things turn back toward minor and our subject reappears, once again in the tenor voice. At this juncture, Bach introduces our first advanced contrapuntal technique: stretto. One beat after the tenor begins, the alto interjects with its own iteration while the soprano provides some lyrical accompaniment.

Stretto is often reserved for later in a fugue, as it effectively heightens drama. While it’s appearance here is relatively early on, Bach mediates the drama by dropping the bass voice. With the bass gone, the texture leans out, the dynamic level drops, and the stretto is only between two of the four voices. After these two middle voices finish their stretto, the outer voices then take their turn: soprano as the leader, bass as the follower. 

After all four voices have cycled through a stretto, we move once again into an episode that is reminiscent of our previous one. There is a lighter texture, a move to the major, and a shift to a fairly high register on the keyboard. However, this respite is also short-lived. We slip back into B-flat Minor, and Bach moves us to our next advanced contrapuntal technique: inversion. Interestingly, the tenor (the last voice to enter originally) kicks off this new technique, reversing course not only with the melodic contour of the subject, but also presentation of the voices. 

Similarly to the stretto, this idea is not realized with all voices at once, but rather with two voices at a time. We begin with the tenor and immediately move into a presentation of the inverted subject in the alto. Then, after the alto is through, we transition to an episode that builds drama and dynamic level, due to musical material being low on the keyboard and densely written. After this, the other two voices (first the soprano, then the bass) are permitted to take their crack at the inversion, and we once again back off into a contrasting episode.

From there, Bach moves into some extra-advanced contrapuntal techniques, beginning by presenting the inverted subject in stretto. Once again, only two voices are used for the stretto (the tenor and soprano). The alto and bass provide accompaniment, and the bass gets a cool repeated gesture to jam out on. This section builds up intensity, as all four voices are present and we are climbing up the keyboard. While this section is exciting to listen to, it is a total nightmare to play. The left hand is awkward, and the right hand has very unintuitive syncopations to manage. It’s hard! 

Welcome to my most often screwed-up spot. 

Once we are through that particular ordeal, Bach repeats the strategy he used during our first stretto: a short episode to lessen the intensity, and then the remaining two voices (alto and bass) take their crack at it. This combination was also super hard! Stretched out hands doing quick notes just isn’t easy to execute. But finally, we are through with the inverted stretto. Our next episode is a friendlier sequence that gets us firmly into major territory — A-flat Major. It’s a ray of sunshine breaking through all this drama, with all four voices leaping upwards to a local high point. 

After this short break, we are introduced to our second extra-advanced contrapuntal technique: subject and inverted subject in stretto. 

The soprano has the inverted subject; the also enters one beat later presenting our original subject. 

The soprano begins with the inverted subject — musical material we are totally accustomed to by now. One beat later, the tenor enters with something we haven’t heard in a while: the original subject. This iteration of the stretto becomes most audible toward the end (listen for the running eighth notes). The top voice runs down while the lower voice runs up, like a dog chasing its tail. As in every previous stretto, Bach shows some restraint and continues presenting his stretto in a two-by-two manner, with an episode separating the two presentations. After the bass and alto get their crack at this stretto (with the bass leading with the original subject, the alto trailing with the inversion), we begin building to the final, most dramatic moments of the fugue. 

As is standard for this fugue, a quick episode dissipates some of the intensity, which allows us to arrive at the final moments with room to grow. Bach presents yet another stretto. However, unlike every stretto up until this point, this time all four voices simultaneously participate. The soprano and alto, in parallel sixths and thirds, start us off with the original subject. The bass and tenor enter, as always, one beat later, with the inverted subject, in thirds. 

The top voices present the original subject in parallel sixths. The lower voices present the inverted subject in parallel thirds. 

The doubled presentations are incredibly striking, with running eighth notes elevating us to our most dramatic moment. Both hands are in parallel thirds; the upper voices climb while the lower voices descend. The density of the writing and extreme use of register indicate that Bach had something loud in mind. (Which is interesting to think about — the most likely instrument for the WTC would have been the harpsichord, which generally only has a single dynamic level. Composers had to use various strategies, such as these, to create a sense of differing dynamic levels. It seems like Bach is reaching beyond his current instrument’s capability and striving toward what another instrument could possibly accomplish.) 

This part is incredibly difficult, and it’s such a bummer that it’s the last thing you do. Parallel thirds are hard on the keyboard, and having a bunch in a row, in both hands moving in opposite directions… Well, it’s just not that fun to execute. 

Parallel thirds, a lot of them, right at the end. Bummer! 

To me, the ending is a bit quirky. It’s completely “correct” from a compositional perspective — we retain our four voices, and each voice moves in a sanctioned manner. But because we have just heard this dramatic buildup with the parallel intervals and have built up so much sound, it always sounded strangely hollow to me that Bach didn’t add bass octaves in the final two measures. (Although, to be fair, his keyboard wouldn’t have accommodated octaves for the penultimate note, and perhaps this is just my ear which has become accustomed to the sound of later Romantic literature.) The single-note bass line never seemed quite dramatic enough after everything we’ve just been through. I ended up tossing in an octave for the final chord, but I was awfully tempted to add octaves for the whole ending. Restraint. 

As I’ve said before, Bach has the reputation of being the best at synthesizing the compositional principles of the High Baroque into his works. In many other posts, I’ve argued that he was actually more innovative than we typically give him credit for. But in this particular fugue, I don’t think there’s a stance to take except that this is an example of exceptional backwards-looking synthesis. To recap, Bach has done the following over the course of this fugue: 

  • Subject
  • Subject in stretto 
  • Inverted subject 
  • Inverted subject in stretto 
  • Inverted subject and original subject in stretto

Furthermore, fragments of the subject often show up throughout the fugue. To take a subject that’s already challenging to work with and present it in four voices is noteworthy. To take that subject and present it in every combination of every form is truly remarkable. It’s an incredible piece of work. So hard to play, but super cool.