hard to overstress the importance of the thoroughbass for Bach. Music theorist Joel Lester goes so far as to say that Bach’s “compositions in all genres … arise from varying and intensifying the musical materials that emanate from textures that themselves result from elaborations of thoroughbass progressions.”52 Bach refers to the thoroughbass as the most perfect foundation of music. It is played with both hands in such a way that the left hand plays the prescribed notes while the right adds consonances