Pieter Dirksen 'Bach's partita 'Ach, was soll ich Sünder machen'
het ORGEL 95 (1999), nr. 1, 14-24 [summary]

J.S. Bach's authorship of the chorale partita BWV 770 'Ach, was soll ich Sünder machen has often been doub-ted, though its outspoken stylistic features and the trustworthiness of the sources leave hardly any room for doubt. It shows the creative response of the young Bach to this supremely Thuringian genre, in particular to the harpsichord-styled chorale partitas of his alleged teacher Georg Böhm. Bach laid a new emphasis on dense counter-point, fullness of harmony, and motivic consistency as well as careful (cyclical) planning of the partita as a whole, and BWV 770 forms in every way a fine example of this individual, new concept. In the extension of the final two varia-tions Bach follows the example of Böhm, adopting the latter's fusion of middle and north German elements. However, Bach goes well beyond his model here, both in length and in for-mal and stylistic audacities, as is espe-cially striking in the Stylus phantasticus manner of the final partita. It seems that BWV 770, following on Böhm's partitas, was primarily intended for harpsichord, including the last two variations, where (most of) the indica-tions for the use of two manuals may be an afterthought of the composer to make the work (also) suited for the organ. All evidence points to a date of composition in the late Arnstadt period, i.e. ca. 1706, BWV 770 takes an honou-red place within a group of large key-board works from this period which can be considered as Bach's first master-pieces.