There are many different questions and issues that come into play when an arranger is faced with deciding whether to change Bach’s original. One of the more straightforward questions arises when two sections are the same–but not quite.
It is easy for us to just assume that Bach sometimes broke conventions “because he could.” However, when Bach does break a rule, it is almost always enlightening to try it ourselves–without the broken rule. Almost invariably, we will run into the same obstacle that Bach himself had confronted!
In the Sonatas and Partitas, that obstacle frequently has to do with the tuning of the violin. However, the guitar has lower notes than the violin, and being tuned in fourths rather than in fifths, there are often times when an inner voice that was not possible on the violin can indeed be played on the guitar.
This third video in the Arranger’s Corner addresses some of these questions as they arose in the Adagio, BWV 1001.