Of the sonatas for German flute which are attributed to Bach, only five can rightly be looked upon as genuine works of the then conductor at the Court of Köthen (c.1720). In Terms of form theses sonatas differ in the degree in which they are related to the four-movement ‘sonata da chiesa’ as well as to the later three-movement type of sonata and to the ‘sonata da camera’, consisting of more movements than one, which resembles the suite.

The sonata in C major and the one in B flat minor cannot easily be classified in this was. In the first movement of the sonata in C major a slow prelude is followed by a masterly fantasia, the melody hovering, as it were, above a pedal note; in the Minuet I a figured bass part becomes a written-out harpsichord part. Moreover, the ‘galant’ quality of this minuet deviates from the late-baroque expressivity of the adagio in A minor.

The features that single out the much more pensive sonata in B flat minor from among the other sonatas of that time are the length of the first movement with its chromatic tensions, as well as the combination of a fugal presto with an allegro gigue in the last movement. Its artistic value – immediately apparent – can be traced in nearly every aspect of the composition.

In his sonata in E minor Bach keeps quite strictly to the style of a ‘sonata da chiese’. Both the way in the first movement that the continuo repeatedly takes up the flute ‘cantabile’, and the liberty, with which Bach uses the bass part (treating it like a solo voice, achieving thereby a chaconne-like effect) are worth mentioning. Of a similar interest is the last movement, with its two themes.

The source of the sonata in E flat major is a copy dating from the middle of the 18th century, the title of which is in the hand-writing of Philipp Emanuel Bach. The conclusion that a younger man than Bach might be the composer of this sonata is borne out by the fact that the harpsichord in the first movement adheres to motifs of its own, which form a lively contrast to the themes of the flute voice, as well as by the sensitive mood and the pastoral touch of the siciliana, and the frequency with which parallel thirds occur in the third movement.

In all four movements of the sonata in E major we meet Bach as the inventor of tuneful melodies; a free-flowing expressive ‘cantilene’ characterises the first movement, as does a ‘galant’ and melodious ‘ ductus’ in siciliano form. In the two quick movements Bach achieves the melodic ideas which were to become the norm in later classical music.

In its written-out three-part harmony, the sonata in a major is the bass part is composed is of particular interest. Not only does is, as is usual, support all the other parts, but – especially in the slow movement – it is of a remarkably melodious quality. The incomplete first movement, difficult to be reconstructed in a satisfactory way, has been omitted in the present recording.

Some notes on the performances on this record: In baroque compositions with a figured continuo part the performers are free to choose their own bass instrument. More often than not they would, and still do, choose the bass-viol. For this recording a bassoon was used – an idea which has the added advantage of distinctly setting off the two-part counterpoint against the flute, and also that of clearly contrasting the harpsichord with the two wind instruments.

It is true that it was occasionally the custom, as with sonatas, for a harpsichord to amplify the bass voice, but the custom was abandoned on the grounds that in a three-part composition (i.e. two equivalent descant voices played by the flute and the harpsichordist’s right hand, plus a bass voice placed by the harpsichordist’s left hand) there was no need for it.

For this recording only modern instruments were used – but the harpsichordist makes allowance for the fact that Bach did not have mechanical pedals by the way in which he uses his stops. A change of the register in the course of one and the same work was therefore only made to the extent possible in the Baroque era, with the few stops that were available at the time.