A man may possess all these qualities, however, and remain an indifferent performer on the Clavier, just as clear and agreeable enunciation does not necessarily make a good speaker. To be a first-rate performer many other qualities are needed, and Bach possessed them all in a notable degree.
Some fingers are longer and stronger than others. Hence players are frequently seduced to use the stronger whenever they can readily do so. Consequently successive notes become unequal in tone, and passages which leave no choice as to the finger to be used may become impossible to play. Bach recognised this fact very early in his career. To get over the difficulty he invented exercises for his own use in which the fingers of both hands were made to practise passages in every conceivable position. By this means every finger on both hands equally became strong and serviceable, [pg 54] so that he could play a rapid succession of chords, single and double “shakes,” and running passages with the utmost finish and delicacy, and was equally fluent in passages where some fingers play a “shake” while the others on the same hand continue the melody.
Besides these improvements, Bach invented a new system of fingering.[122] Before his time, and even in his early years, it was usual for the player to pay attention to harmony rather than counterpoint. Even so it was not customary to use every one of the twenty-four major and minor keys. The Clavichord was still what we term “gebunden”; that is, several keys struck the same string, which, therefore, could not be accurately tuned.[123] Consequently it was usual to employ only those keys whose notes were tuned with some approximation to accuracy. Again, [pg 56] good players in those days hardly ever used the thumb, except when a large interval had to be stretched. But when Bach began to melodise harmony so that his middle parts not merely filled in but had a tune of their own, when, too, he began to deviate from the Church modes then in general vogue in secular music, using the diatonic and chromatic scales indifferently, and tuning the Clavier in all the twenty-four keys, he found himself compelled to introduce a system of fingering better adapted to his innovations than that in use, and in particular, to challenge the convention which condemned the thumb to inactivity. It is held by some writers that Couperin forestalled Bach's method of fingering, in his L'Art de toucher le Clavecin, published in 1716. But that is not the case. In the first place, Bach was above thirty years old in 1716, and had already developed a distinctive method of his own. And in the second place, Couperin's system differs materially from Bach's, though both made more frequent use of the thumb than was so far customary. When I say “more frequent use” I do so advisedly; for whereas in Bach's system the thumb is the principal finger—for the difficult keys, as they are called, are unplayable without it—it is not equally indispensable with Couperin, whose thematic material was not so intricate as Bach's, nor did he compose or play in such difficult keys. Consequently Couperin [pg 56] had not an equally urgent need to use the thumb. We need only compare Couperin's with Bach's system of fingering, as Carl Philipp Emmanuel explains it,[124] to discover that Bach's permits every passage, however intricate and polyphonic, to be played with ease, whereas Couperin's is hardly effective even for his own compositions. Bach was acquainted with Couperin's works and highly esteemed them,[125] as he did those of other French Clavier composers, for their finish and brilliance. But he considered them affected in their excessive use of ornaments, scarcely a single note being free from them. He held them, also, superficial in matter.
Bach's easy, unconstrained use of the fingers, his musical touch, the clearness and precision of every note he struck, the resourcefulness of his fingering, his thorough training of every finger of both hands, the luxuriance of his thematic material and his original method of stating it, all contributed to give him almost unlimited power over his instrument, so easily did he surmount the difficulties of its keyboard. Whether he improvised or played his compositions from notes, he systematically employed every finger of each hand, and his fingering was as uncommon as the compositions themselves, yet so accurate that he [pg 57] never missed a note. Moreover, he read at sight other people's compositions (which, to be sure, were much easier than his own) with the utmost facility. Indeed, he once boasted to a friend at Weimar that he could play at sight and without a mistake anything put before him. But he was mistaken, as his friend convinced him before the week was out. Having invited Bach to breakfast one morning, he placed on the Clavier, among other music, a piece which, at a first glance, seemed perfectly easy. On his arrival, Bach, as was his custom, sat down at the Clavier to play or look through the music. Meanwhile his friend was in the next room preparing breakfast. In a short time Bach took up the piece of music destined to change his opinion and began to play it. He had not proceeded far before he came to a passage at which he stopped. After a look at it he began again, only to stop at the same place. “No,” he called out to his friend, who was laughing heartily in the next room, “the man does not exist who can play everything at sight. It can't be done.” With that he got up from the Clavier in some annoyance.[126]
Bach also could read scores with remarkable facility and play them on the Clavier. He found no more difficulty in piecing together the [pg 58] separate parts when laid side by side before him.[127] He often did so when a friend brought him a new Trio or Quartet for Strings and wished to hear how it sounded. If a Continuo part, however badly figured, was put before him he could improvise a Trio or Quartet upon it. Nay, when he was in the mood and at the height of his powers, he would convert a Trio into a Quartet by extemporising a fourth part. On such occasions he used a Harpsichord with two manuals and pedal attachment.
Bach preferred the Clavichord to the Harpsichord, which, though susceptible of great variety of tone, seemed to him lacking in soul. The Pianoforte was still in its infancy and too coarse.[128] [pg 59] Both for practice and intimate use he regarded the Clavichord as the best instrument and preferred to express on it his finest thoughts. He held the Harpsichord, or Clavicembalo, incapable of the gradations of tone obtainable on the Clavichord, an instrument which, though feeble in quality, is extremely flexible.
No one could adjust the quill plectrums of his Harpsichord to Bach's satisfaction; he always did it himself. He tuned his Harpsichord and Clavichord, and was so skilful in the operation that it never took him more than a quarter of an hour. It enabled him to play in any key he preferred, and placed the whole twenty-four of them at his disposal, so that he could modulate into the remoter as easily and naturally as into the more nearly related keys. Those who heard him frequently could hardly detect the fact that he had modulated into a distant key, so smooth were his transitions. In chromatic movements his modulation was as easy and sequent as in diatonic. His Chromatic Fantasia, which is now published,[129] bears out my statement. In his extemporisation he was even freer, more brilliant and expressive.
When he played his own music Bach usually adopted a brisk pace. He contrived to introduce so much variety that every piece became a sort of conversation between its parts. If he wished to express deep emotion he did not strike the notes with great force, as many do, but expressed his feeling in simple melodic and harmonic figures,[130] relying rather on the internal resources of his art than external dynamics. Therein he was right. True emotion is not suggested by hammering the Clavier. All that results is that the notes cannot be heard distinctly, much less be connected coherently.