Note: Numbers inside triangles indicate strings whose vibrations need to be checked by the given finger of the left or right hand. When this symbol is accompanied by the abbreviations w, th, or dp, the meaning is to stop the vibration of the string by means of the RH wrist, heel (thumb-side), and distal phalanx of the thumb respectively. The difference between stopping the sound with “p” (thumb) and “dp” is that the first makes use of the thumb pad (as if playing the string) while the latter checks the string’s vibration by means of the side of the thumb’s distal phalanx (i.e., placing the thumb ‘under’, not on, the string). The latter technique is useful when ascending to an adjacent string, not wishing both to sound together. Not all such techniques are explicitly indicated. The most common damping technique is a (light) rest stroke, when descending across adjacent strings that form a major/minor 2nd, e.g., a rest stroke on string 10 after sounding string 9, leaving 10 to sound while checking 9 by coming to rest on it. Occasionally it is a good idea to fret the A2 bass on string 9/10 instead of playing it open when it is followed by an open 9th string (i.e., G#2 or G2). This avoids the melodic (M/m) 2nd becoming a dissonance as well as unnecessarily tricky damping. There is an example of this fingering in the Kellner Giga: the anacrusis or pickup from bars 3 to 4, page 2, system 2.
Note: Narciso Yepes used a half capo tasto at III when he performed this prelude. While avoiding the extended barre of mm. 1-4, this solution (like most six-string guitar editions) makes it impossible to play the correct bass note on page 2, system 4, m. 2 (p. 1, system 6, m. 2 of the Urtext). I prefer to do away with the capo altogether, a solution which opens again other possibilities. One of these is occasionally to fret the bass line on strings 8-10, avoiding disruptive mid-phrase changes of position. Interpretive merits aside, for the advanced ten-string guitarist the result is also a good technical study in extended use of the fingerboard, and for the agility of the right hand thumb (strings 7-10 are used 46 times in this brief composition).
(Clearly I disagree with the assumed “fidelity” of formalist “executions” of the text that “read” literal “intentions” into rests. There are examples in Bach’s music where such textualism results in obvious nonsense, e.g., four one-bar phrases of a single melodic line, with big leaps, instead of one four-bar phrase in steps and two-part counterpoint at the beginning of the Sarabande of BWV 995. Nevertheless I believe in the value of a plurality of different interpretations, so I may well formalize or “rhythmicize” some future performance, just as I may take the tempo slower or quicker, bring out other implied voices, or apply other articulations and dynamics. Why not? For an excellent demonstration of such possibilities in Bach – but not necessarily just in Bach – see this lesson by pianist-composer Emile Naoumoff.)