Czech Chamber Music Society • Mahan Esfahani

In the early 1720s, the Köthen Kapellmeister Johann Sebastian Bach (1685–1850) undertook a daring project: creating a series of piano compositions in all 24 major and minor keys so the instrument would sound relatively “good” in every tonality, without unpleasant intonation problems. For today’s listeners, such an idea seems commonplace—the choice of keys is not limited, and lots of sharps or flats just make the music more challenging for musicians to learn; the differences are not apparent to audiences. That was not the case 300 years ago.

Bach’s Well-Tempered Clavier (Das wohltemperierte Clavier), completed in 1722, was an ambitious answer to one of the key questions of musical practice at that time: how to reconcile composers’ growing tonal ambitions with the technical possibilities of keyboard instruments and the established systems used for their tuning. Older tuning systems, and the mean-tone temperament in particular, treated some keys preferentially, while others sounded so out of tune that they were unusable. “Well-tempered” tuning (unlike today’s equal temperament) meant making compromises in the division of the octave, enabling the use of all keys with acceptable intonation, but at the same time, each key retained the character of its own peculiar colouring. Bach’s cycle was thus significant as a demonstration: the set of 24 preludes and fugues in all major and minor keys represented practical proof that the new way of tuning opened up previously unsuspected possibilities for composers and performers. At the same time, it was intended as a carefully conceived pedagogical collection. As Bach himself wrote in the foreword, it was to serve “for the profit and use of the studious musical young”, but also “for the special diversion of those who are already skilful in this art”. Book I thus combines an experiment and a systematic approach with stylistic variety concealed within.

Bach wrote Book II of the Well-Tempered Clavier from 1738 to 1742 in reaction to the huge demand for Book I, but by then his personal and professional situation was entirely different. Since 1723, he had been working in Leipzig as the cantor at the St Thomas Church, busy with the routine musical operations of the church and of the school connected to it. At the same time, the huge amount of experience he had accumulated from many years of creative work led him to undergo an extraordinary stylistic synthesis. One example of this is the continuation of the Well-Tempered Clavier, which no longer needed to prove the benefits of tempered tuning. While Book I might resemble a catalogue or encyclopaedia of possibilities, which Bach was trying out for the first time in many cases, Book II seems more intricate, concentrating on the greatest possible internal coherence and the expressive depth of the individual pieces, while taking the framework of all 24 keys for granted. Here, too, the fugue in each key is preceded by a prelude. Often longer and more richly layered, the preludes are stylistically more concrete, revealing the influence of dance forms, the Italianate concertante style, and the sonata da camera. Some of the preludes seem almost like improvisations, while others, to the contrary, exhibit strict architecture and formal complexity. In the fugues of Book II, Bach is at the pinnacle of his contrapuntal artistry. Here, he fashions longer, more distinctive subjects and develops them with unparalleled rigor, employing every method that has ever appeared in the history of the fugue. In terms of form, they exhibit greater maturity and substance than the fugues of Book I.

Bach’s handling of keys, forms, and affects (the basis of Baroque musical aesthetics) is also much more purposeful. Each key embodies its own specific affect, sometimes subtly suggested, at other times strongly expressed. The Prelude in C major opens the cycle with dense, almost orchestrally conceived writing that gives us an idea of the whole work’s gravity. The following fugue, propelled by an energetic and rhythmically potent theme, stands as a confident declaration of internalized creative purpose, devoid of didacticism or experimentation. Examples of bold affects are found in the Prelude and Fugue in C minor: the prelude is austere and disciplined, almost ascetic in character, while the fugue—with its rhythmically incisive theme and unrelenting flow of voices—creates a tension that is characteristic of Bach’s late Leipzig period. The Prelude and Fugue in E flat minor offers a similar contrast: the prelude, with its darkly chromatic harmonies, runs its course slowly and deliberately, while the fugue abounds with contrapuntal invention.

The preludes inspired by dance forms or concertante models open up an entirely different world. The Prelude in D major resembles an Italian concerto with its brilliant figuration, and it makes great demand on the performer’s skill. On the other hand, the light, secular character of the transparently galant Prelude in G major stands in stark contrast to the strictly conceived fugue that follows. For the fugues of Book II, Bach created themes that are often extraordinarily characterful. The Fugue in F sharp minor is one of the lengthiest in the entire Well-Tempered Clavier, and the long, melancholic arch of the theme speaks with profound spiritual weight. Similarly monumental is the Fugue in B flat minor, for which Bach, to the contrary, invented a short, unobtrusive theme, but on its basis he proceeds to build his architecture with extraordinary patience and logic. Elsewhere, however, he permits himself a more playful approach within the framework of the rules of counterpoint. Examples include the Fugue in F major and the Fugue in A major, crafted with lightness and elegance, proving that formal rigor does not necessarily mean monotony. Even within the framework of a strict form, Bach can astonish us with nuances of expression.

It is Bach’s ability to imbue every key and every prelude and fugue pair with a unique character that makes Book II of the Well-Tempered Clavier special. The cycle makes the impression of a carefully crafted whole, in which there is an alternation between seriousness and lightness, rigour and lyricism, and introspection and the joy of playful musicmaking. This balance between order and freedom is a reflection of Bach’s mastery in his late period, and it is also the reason why Book II is still regarded to this day as one of the most demanding, yet also most rewarding challenges of the keyboard literature. The clear signs of a mature work found in Book II place it alongside Bach’s other late cycles like the Musical Offering or the Art of the Fugue, in which order and freedom find a perfect equilibrium. Book II of the Well-Tempered Clavier thus represents not only one of the pinnacles of the keyboard literature, but also unique testimony to the direction taken by Bach’s musical thinking over two decades. Less overtly brilliant then Book I, Book II has greater depth and concentration, posing increased challenges to interpreters, time and again affirming Bach’s standing as one of history’s supreme masters of counterpoint and musical architecture.

Both books of the Well-Tempered Clavier have served as inspiration for later generations of composers, whether in terms of the handling of keys in the layout of a cycle of compositions of the same type or the perfection of the contrapuntal writing. Chopin’s 24 Preludes, Op. 28 exhibit a clear connection to the Well-Tempered Clavier, and Shostakovich openly admitted his debt to Bach in his 24 Preludes and Fugues, Op. 87. Hindemith’s 1942 piano cycle Ludus tonalis is often called the “Well-Tempered Clavier of the 20th century”. Inspiration, whether acknowledged or unconscious, is more closely connected to Book II of Bach’s cycle because of its sophistication. It is no wonder that it was also the fugues of Book II that the young Mozart selected; he often enjoyed arranging Bach’s smaller-scale compositions of all kinds, primarily to learn all the secrets of the master’s perfect counterpoint. Although he then pursued a different stylistic path, Bach’s Well-Tempered Clavier undoubtedly inspired him to strive for perfection.