Geoffrey Thomas

According to Sebastian Bach’s manner of placing the hand on the keyboard the five fingers are bent so that their points come into a straight line, and fit the keys, which lie in a plane surface under them, that no single finger has to be drawn nearer when it is wanted, but every one is ready over the key which it may have to press down. What follows from this manner of holding the hand is:

1. That no finger must fall upon its key, or (as also often happens) be thrown on it, but only needs to be placed upon it with a certain consciousness of the internal power and command over the motion.
2. The impulse thus given to the keys, or the quantity of pressure, must be maintained in equal strength, and that in such a manner that the finger be not raised perpendicularly from the key, but that it glide off the forepart of the key, by gradually drawing back the tip of the finger towards the palm of the hand.
3. In the transition from one key to another, this gilding off causes the quantity of force of pressure with which the first tone has been kept up to be transferred with the greatest rapidity to the next finger, so that the two tones are neither disjoined from each other nor blended together. The touch is therefore, as C. Ph. Emanuel Bach says, neither too long nor too short, but just what it ought to be.

The advantages of such a position of the hand and of such a touch are very various, not only on the clavichord, but also on the pianoforte and the organ. I will here mention only the most important.

1. The holding of the fingers bent renders all their motions easy. There can therefore be none of the scrambling, thumping, and stumbling which is so common in persons who play with their fingers stretched out, or not sufficiently bent.
2. The drawing back of the tips of the fingers and the rapid communication, thereby effected, of the force of one finger to that following it produces the highest degree of clearness in the expression of the single tones, so that every passage performed in this manner sounds brilliant, rolling, and round, as if each tone were a pearl. It does not cost the hearer the least exertion of attention to understand a passage so performed.
3. By the gliding of the tip of the finger upon the key with an equable pressure, sufficient time is given to the string to vibrate; the tone, therefore, is not only improved, but also prolonged, and we are thus enabled to play in a singing style and with proper connection, even on an instrument so poor in tone as the clavichord is….

The natural difference between the fingers in size as well as strength frequently seduces performers, wherever it can be done, to use only the stronger fingers and neglect the weaker ones…. Bach was soon sensible of this; and, to obviate so great a defect, wrote for himself particular pieces, in which all the fingers of both hands must necessarily be employed in the most various positions in order to perform them properly and distinctly. By this exercise he rendered all his fingers, of both hands, equally strong and serviceable, so that he was able to execute not only chords and all running passages, but also single and double shakes in which, while some fingers perform a shake, the others, on the same hand, have to continue the melody…

When Bach began to unite melody and harmony so that even his middle parts did not merely accompany, but had a melody of their own, when he extended the use of the keys, partly by deviating from the ancient modes of church music, which were then very common even in secular music, partly by mixing the diatonic and chromatic scales, and learned to tune his instrument so that it could be played upon in all the 24 keys, he was at the same time obliged to contrive another mode of fingering, better adapted to his new methods, and particularly to use the thumb in a manner different from that hitherto employed….

From the easy, unconstrained motion of the fingers, from the beautiful touch, from the clearness and precision in connecting the successive tones, from the advantages of the new mode of fingering, from the equal development and practice of all the fingers of both hands, and, lastly, from the great variety of his figures of melody, which were employed in every piece in a new and uncommon manner, Sebastian Bach at length acquired such a high degree of facility and, we may almost say, unlimited power over his instrument in all the keys that difficulties almost ceased to exist for him.