Beckemeyer joins Bach specialist Koji Otsuki in a very special program of five obbligato violoncello piccolo arias. Beckemeyer will perform with Otsuki “Woferne du den edlen Frieden” from BWV 41, Jesu, nun sei gepreiset, and “Ich fürchte nicht des Todes Schrecken” from BWV 183, Sie werden euch in den Bann tun.

The violincello piccolo is subject to much debate:

Although cellos with four strings predominated in Italy by the end of the 17th century, cellos with more than four strings were still used elsewhere. The advent of thumb position fingerings (the technique in which the whole hand is put on top of the strings with the thumb placed across and perpendicular to them, functioning as a moveable nut in relation to the other fingers) may have caused the redundancy of cellos with more than four strings at the beginning of the 18th century. However, five-string cellos were used in Germany into the middle of the 18th century. In addition to J.S. Bach's solo cello suite no.6 BWV 1012, written for a five-string cello, the cello part of his cantata "Gott ist mein König" BWV 71, requires a range extended to c'' (f'' in Bach's original, unorchestrated version), suggesting that an E string would have been required for the execution of this part. Five-string cellos also appear in numerous Dutch, Flemish and German paintings and etchings from the 17th and 18th centuries. (see fig.2).
The correct definition of the violoncello piccolo has been widely debated. At least eight of Bach's cantatas written between 1724 and 1726 have obbligato parts designated as such. The term piccolo means 'small'. An original cello pattern of Antonio Stradivari is labelled forma B piccola di violincello but it is likely that Stradivari sought simply to distinguish this new smaller pattern from his earlier larger instruments. But these violoncello piccolo parts by Bach imply that a four-string cello tuned G-d-a-e' was used.

A late 18th-century account by E.L. Gerber (whose father was a student of Bach) claimed that Bach invented a special sort of small cello or large viola - called a viola pomposa - to facilitate the execution of rapid obbligato parts in the bass (see W. Neumann and H.-J. Schulze, D1972, p.469). Dreyfus (D1987) has suggested that this instrument may have been the same as the "Viola da spalla" ('shoulder-viola') mentioned by J.J. Walther in his Musicalisches Lexicon (Leipzig, 1732), which was tuned like a cello but with an added fifth string and held over the shoulder by a strap. However, there is evidence of the earlier existence of both small and large four- and five-string instruments (Stradivari, apparently, also made a five-string viola), and it seems doubtful that this was actually Bach's invention. Rather, it reflects the broad variety of instrument sizes and types still being used in Germany around 1720, and the terminological amibiguity associated with them. (Surviving instruments that may be examples of the viola pomposa, viola da spalla, or violoncello piccolo are listed by M.M. Smith, B1998.)