Sonata in A for flute and cembalo, first movement, BWV 1032/1

The original is preserved in Bach's autograph manuscript D B Mus. ms. Bach P 612 together wtih the double concertoBWV 1062. The two pieces are preserved in a unique layout, used to save paper, in which the concerto is written acrossthe top of each sheet, the sonata occupying only the bottom two staves. These have been cut away between m. 63 andthe last four measures of the first movement, leaving a gap of approximately 46 measures. Whether Bach or someoneelse made the excision is unknown; it is equally uncertain whether the missing measures contained any passages thatBach had crossed out or intended to replace. Thus there is no guarantee that 46 measures are actually missing, but thepresent version follows that assumption. Many other reconstructions have been attempted. The present one is based onthe principle of filling in the gap with transposed restatements of material actually by Bach, with the upper partsexchanged.