Playing the clavichord demands a paradoxical control: one should press the key fast enough, but without pushing the string up, in order to produce a sufficiently loud sound but also to maintain a correct intonation. Historical sources on keyboard technique in Johann Sebastian Bach’s circle describe finger motions (“tire” or “Schnellen”) that seem particularly suited to the simultaneous control of the speed and depth of touch. After a theoretical study that establishes the relationship between the movement of the key, sound intensity and intonation, an experimental study measures these quantities for a “pushed” or vertical touch and for a “pulled” touch, with a gliding motion of the fingertip towards the hand palm. The results indicate that the paradoxical control demanded by the specific mechanics of the clavichord is advantageously achieved by the gesture described in historical sources (a circular withdrawal movement of the fingertip).