“A sincere guide, wherein lovers of the clavier, and especially those desirous of learning, are shown a clear method not only (1) to play two voices cleanly, but also, upon further progress, (2) to handle three obbligato voices correctly and skillfully, and at the same time, not merely to acquire inventions, but to develop them skillfully, and above all, to acquire a firm cantabile style of playing, and furthermore, to be taught a clear method for cultivating a strong interest in composition. Completed by Johann Sebastian Bach, Capellmeister to the Prince of Anhalt-Cöthen. 1723.”

 Bach himself inscribed this on the title page of the completed collection. The Inventions and Sinfonias are revisions of short pieces compiled for the lessons of his eldest son, Friedemann, and thus, by their very origin, possess the character of a pedagogical work. But what is the true meaning of what is written here?

 Bach began the training of musicians by having them acquire keyboard playing technique using both hands. This was to acquire a more natural musicality by connecting it with hand movements. However, the method employed here is not the basso continuo peculiar to the Baroque era, i.e., supplementing the bass with appropriate chords in the right hand. All voices are indispensable “obbligato” parts, written to be played “cantabile.” And each independent voice merges into one within the harmony. Strict counterpoint and cantabile, melody and harmony. The seemingly simple two- and three-voice works actually bear the significant aesthetic proposition of “unity in diversity” from the 16th-17th centuries.

 The word “Inventio” in Bach’s message is also related to the aesthetics and compositional methods of older music. This term originates from rhetoric and is often translated as “idea” or “conception,” but it originally means “discovery” (not “invention”). That is, to find expressions appropriate to the content one wishes to convey. To do so, one must learn as many rhetorical figures (figurae) as possible and understand their arrangement. The Inventions and Sinfonias are written as exemplars of this, showcasing the extremely diverse styles of Bach’s keyboard music. They are, so to speak, a microcosm of Bach’s musical world.

 Therefore, “Invention” is by no means a term representing a specific genre or musical form. While some collections by German composers before Bach bear this title, there is no formal unity or commonality among them. After Bach, if the term “Invention” is used in a general sense in musical analysis, it would be in a positive context, referring to a concise yet well-structured contrapuntal work exemplary in style and technique, or as an homage to Bach’s masterful compositions.

 The composition period is 1720-23, a time when Bach was employed at the court of Cöthen and produced numerous instrumental works. In 1720, Bach began compiling a music notebook for his eldest son, Friedemann, who was then 10 years old. In this notebook, two-voice Praeludia and three-voice Fantasias were inscribed in the order of C major, D minor, E minor, F major, G major, A minor, B minor, B-flat major, A major, G minor, F minor, E major, E-flat major, D major, C minor (though the three-voice C minor is missing). The arrangement was related to the number of key signatures. When he fair-copied this in 1723, he revised the pieces themselves, rearranged them in diatonic order, and named the two-voice pieces Inventions and the three-voice pieces Sinfonias.

※ Please also refer to the section on ‘Sinfonia’.

No. 5 in B-flat major, BWV 776

 Since the subject and countersubject are presented simultaneously from the outset, the piece takes on the character of a double fugue. The two subjects contain all sorts of contrasts, such as ascending and descending motion, a leisurely rhythm with ornaments versus perpetual motion in sixteenth notes, and arpeggiated chords versus stepwise motion. Consequently, even without overly complex contrapuntal treatment, merely interchanging the voices of each motive generates a wide variety of variations. Furthermore, the performer can freely add ornaments to imbue the progression of the piece with their own unique color.

 Another reason why this piece, despite its very few motives, does not become monotonous lies in the skillful use of sequential progression to create key transitions. Since the subject itself ends on the dominant, after starting in E-flat major, it immediately moves to the dominant key (B-flat major). Thereafter, the opening motif, usually repeated twice, is repeated five times, including in the left hand, opening the way to C minor. However, in measure 15, by changing the ascending arpeggiated octave to a minor seventh, F minor is secured. This technique is repeated in the next four measures, leading temporarily to B-flat minor. But even this is thwarted as the opening motive, which should have continued ascending from measure 20, descends instead, pushing it back to F minor. Thus, in the middle section, unstable minor key areas persisted, but by having both hands leap by a second multiple times in measure 24, it finally breaks out into A-flat major, achieving a return to E-flat major in the next statement. In this way, the entire piece weaves a drama around the tonic key.