Friedrich Hermann's Bach preface (English translation)
It was a great merit of the Leipzig concert master and outstanding violinist Ferdinand David, to have made these sonatas in a playable edition about half a century ago, and with it he gave violinists some very exciting study material; previously, these sonatas had been an unsolved riddle for many. David understood not only how to provide excellent fingering and bowing; in order that the thematic element be fully realised, he also, as a sensitive musician, brought light and shade to the work. A particular difficulty in the execution of these sonatas is that in three- and four-part writing the player struggles with the curve of the bridge. This compels him to leave quickly the bass notes which Bach wrote as held notes, in order to reach the upper strings. In this regard, David only had skilled artists in mind in his edition, he left much as it is found in the originals, with the intention that the player should at least be satisfied by the eye when it is impossible that all three or four voices can be heard together. Here now appears the difference between the David's edition and the present one; in the latter, which is intended for teaching, the editor seeks to present the text in the way it can be played, but also how it should be played. The result of this process may appear strange to connoisseurs, but the disciples of art will, using this edition, know exactly when two parts are to be played with equal volume and when one is only to be played as an accompaniment to a melody.
As well as adapting these sonatas for teaching, the editor also sought to solve the problem of making Schumann's piano accompaniment accord with the violin part. This was not as easy as one might think. Such an individual spirit as Schumann also wanted to go his own way in writing an accompaniment and thus, particularly with regard to dynamic level, the great tone-poet and the practical violinist come to differing conclusions. Schumann was not always right; often he required a passage to be played quietly, which it was impossible for the performer not to play loudly.
The violin part that is printed above Schumann's piano part is Bach's original, with a few unimportant alterations, only concerning the performance of arpeggios. Finally, it should be mentioned that the editor could not find a good reason why the first sonata in G minor only has one ♭ in the original as well as the editions that have appeared so far. In the present edition the sonata finally gets its proper tonality through the key signature of two ♭s.