In the years spent at the Köthen court (1717-1723) Johann Sebastian Bach threw himself into composing instrumental music, without a moment’s regret for the Weimar organ or the Lutheran cantatas. The 22-year-old Prince Leopold, a good musician himself, ran a Calvinist court, and was a bit suspicious of liturgical music. So here we have Bach composing instrumental music – profane when vocal – with the vigor, determination and joyfulness that inspired the Concerts accomodés à plusieurs instruments (which we generally know as the “Brandenburg concertos”), the first book of the Well-Tempered Clavier, six sonatas for violin and cembalo and six violin solos (1720) with their cello counterpart in the six Suites, possibly written for Christian Ferdinand Abel, violinist and cellist, who had played for more than twenty years in the Köthen Cappella, an exceptional little pearl that attracted any major musician who happened to be passing by.
The cello suites illustrate Bach’s exquisite balance between the absolute and the aims of teaching: technically the first three are the easiest, and the last three become progressively more complex.   They follow the conventional sequence of Allemande-Courante-Sarabande-Gigue with a Prélude to start with and, in line with French taste but with Bach’s own mathematical rigor, there are a couple of minuets in the first and second suites, Bourrées in the third and fourth, Gavottes for the fifth and sixth, with the obligatory Gigue.
In the Allemande, Courante and gallant dances melody and harmony blend and the series is united by counterpoint. Partly using the open strings – and drawing on the ample existing music for viola da gamba – this monodic bass instrument almost miraculously becomes polyphonic.This effect is heightened in the austere, introspective Préludes – like the second suite – and in slow, thoughtful dances like the Sarabande. The Allemande in the sixth suite is actually written for a five-stringed cello (instead of the usual four-stringed instrument) just to show off the difficulty.
Despite the large-scale impression of improvisation, counterpoint runs through the Préludes where the instrumental line is unbroken (third, fourth, six suites). The fifth is the model, in a severe Lutheran C minor; this is a passage of great breadth and depth, on the pattern of the Prelude and Fugue reflected in the Allemande. In the fifth suite, Bach returns to his trick of tuning the A-string down to G.

Alberto Cantù