Bach produced an extremely rich collection of pedagogical materials, both in content and number of pieces, including The Well-Tempered Clavier, Inventions, and Sinfonias. These were developed from the outset with clear and meticulous planning, often involving selections from several candidates to suit specific purposes, as well as transpositions and revisions. Consequently, there are also numerous works that were not incorporated into the collections, pieces presumed to be original versions in different keys, and simplified early drafts. The 9, 6, and 5 Little Preludes are likely compilations of such short pieces by later generations, also transmitted from pupil to pupil as pedagogical material. The arrangement and popularization of these collections are thought to have been established by the mid-19th century through the Peters Edition's keyboard works (edited by Czerny/Griepenkerl).

The 5 Little Preludes are a group of pieces transmitted solely through the manuscript copies of Johann Peter Kellner (1705-1772), a generation younger than Bach. Kellner was an admirer and collector of Bach's works. He acquired numerous works, and his collection includes valuable materials. However, regarding this particular group of works, no one other than Kellner copied them, and Kellner himself did not attribute them to a composer, leaving their authenticity unresolved. Furthermore, they were previously sometimes referred to as "6 Little Preludes" with the inclusion of Prelude BWV 999. However, BWV 999, which would be the sixth piece, is believed to have originated as a lute piece, and it is now customary to refer to them as "5 Little Preludes."

No. 1 in C Major, BWV 939

It begins with arpeggiated chords of a C major cadence. It somewhat resembles the first prelude of the Inventions or The Well-Tempered Clavier, Book II. The respective domains created by the B natural of the dominant chord of the subdominant and the F-sharp of the dominant chord of the dominant are naturally linked through the tonic key. In the final four measures, the texture suddenly thickens with eighth notes in both hands, followed by brilliant sixteenth-note passagework, gradually slowing down with eighth notes and quarter notes to conclude. This compositional structure is well-crafted for a short piece.

No. 2 in D Minor, BWV 940

After the complete form of the theme is presented three times in both hands in the first three measures, the piece develops using only this material. Both hands attempt to introduce the theme in alternation, but the theme becomes increasingly fragmented and is never fully completed.

No. 3 in E Minor, BWV 941

A dance-like short piece in triple meter. In the latter half, the hands alternate at the center of the measure, i.e., at 1.5 beats, and this slight overlap of parts creates nuance. Although complex harmonic progressions or contrapuntal techniques are not employed, it is a graceful work full of lyricism.

No. 4 in A Minor, BWV 942

The unique sound and atmosphere of this piece are brought about by sequential progression rather than chromaticism. The tonic key is already ambiguous in the first two measures, and from the third measure onward, the destination becomes increasingly blurred due to double appoggiaturas (where appoggiaturas, i.e., ornamental non-harmonic tones forming a minor second, appear simultaneously in multiple voices). Such a progression is unusual for Bach, and without firm evidence, it is difficult to believe it is an authentic work. Nevertheless, it is a short piece with an enjoyable quirky and rugged sound.

No. 5 in C Major, BWV 943

In contrast, this piece exemplifies Bach's typical C major style. It resembles Sinfonia No. 1 or the Fugue from The Well-Tempered Clavier, Book I. Being more than three times longer than the preceding four pieces, it exhibits ingenuity in its key transitions. The four measures from the middle section (measure 16), which begins in the dominant key, juxtapose the dominant key (G major) with its dominant (D major) and the parallel minor of the latter (D minor), transitioning to D major by concluding on a major triad in measure 21. In measure 29, the first half of the middle section concludes in the dominant key, and thereafter, the piece moves towards the tonic, occasionally incorporating subdominant chords. In these two middle sections, the sharp-key's keen brightness and the flat-key's cheerful warmth are well contrasted. It is a fine work that sounds beautiful not only on piano and harpsichord but also on organ.