October 9, 2026
Performance Record of J. S. Bach – Sinfonia No. 1 in C Major, BWV 787
Overview: A performance and personal musical analysis of J. S. Bach's Sinfonia No. 1 in C Major, BWV 787. Reiji examines the recurring appearances of the main theme, including its fragments and inversions, and considers how these interconnected elements shape the composition. His interpretation also explores the perceived tonal progression, changes in musical color, and the expressive significance of particular notes within the piece. These observations inform his approach to emphasizing thematic clarity and the contrasting characters of different passages.
Note: All content on this page is originally explained by Reiji in Japanese. The English version is translated by AI and structured by a parent, with Reiji's final approval.
Reiji's Words and Ideas
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Performer's Notes:
I feel that this piece contains more imitation of the main theme than many other pieces.
When I roughly counted the appearances of the theme throughout the piece, including fragments and inversions (forms in which the direction of the melodic movement is reversed), I found approximately 24 occurrences. The score seems to be almost completely filled with the theme, leaving hardly any space without it.
In many places, the original form of the theme seems to lead into its inversion, while the inversion, in turn, leads back into the original form.
There is only one passage in the piece where a fragment of the theme appears on its own. This occurs from measure 7 through the first half of measure 8. I feel that this fragment serves as a bridge between the inverted form of the theme in measure 6 and the theme that appears in the second half of measure 8.
The piece feels to me like a puzzle constructed from interconnected pieces of the theme. With this in mind, I tried to perform it in a way that allows each appearance of the theme to stand out clearly.
Regarding the tonal progression, I interpret the piece as moving from the tonic key of C major to the dominant key of G major, then to D minor, the relative minor of the subdominant key F major, before moving to F major and finally returning to the tonic key of C major.
On the circle of fifths, D minor is the relative minor of F major, which lies two steps in the flatward direction from G major, passing through C major. Rather than simply moving to a closely related major key, the music shifts into the sound of a minor key, which I find to be one of the distinctive features of this piece.
This change is particularly noticeable from measures 7 to 13. The music begins with a bright impression, then suddenly changes to a darker, gray-like color. From there, it settles into a warmer atmosphere before returning to a brighter character.
In this performance, I paid particular attention to the C-sharp that stands out within this tonal progression, treating it as a kind of anchor within the entire piece and bringing it into focus.
*These notes reflect the performer's own musical analysis and personal interpretation of the piece.
| URL | https://youtu.be/WsefTDQMD8Q |
|---|---|
| Work Information |
J. S. Bach: Sinfonia (Three-Part Invention) No. 1 in C Major, BWV 787 From Inventions and Sinfonias |
| Reference Sheet Music |
G. Henle Verlag: J. S. Bach, Inventions and Sinfonias IMSLP / Petrucci Music Library (public-domain score) |
| Performance |
Piano Performance: Reiji |
| Recording date |
October 9, 2026 Performance by a 10-year-old |
AI Assistant’s Notes and Inferences
- Thematic recurrence and structural perception: Reiji approaches the composition through the repeated appearances and transformations of its principal theme. His approximate count of 24 occurrences includes complete statements, fragments, and inversions. Rather than treating these appearances as isolated events, he considers their relationships as elements of a continuous musical structure. The count reflects his own analytical observations rather than an independently verified thematic inventory.
- Relationships between original and inverted forms: His attention to the transitions between the original theme and its inversion suggests an interest in how contrapuntal material generates continuity. In particular, he interprets the thematic fragment spanning measures 7–8 as a connecting element between surrounding statements. The puzzle analogy expresses his perception of the composition as an interconnected system of musical ideas.
- Tonal progression as an interpretive framework: Reiji describes a tonal trajectory from C major through G major, D minor, and F major before returning to C major. His discussion distinguishes the relationships between keys on the circle of fifths from the contrasting tonal characters he perceives. This is presented as his own hearing and harmonic interpretation, not as a definitive formal analysis of the score.
- Translation of harmonic perception into musical color: The description of measures 7–13 as a progression from brightness to a darker, gray-like color, followed by warmth and a return to brightness, illustrates how Reiji connects harmonic observations with subjective auditory impressions. These color associations provide an expressive framework for his performance rather than serving as objective properties of the harmony.
- Analytical decisions informing performance: Two specific priorities emerge from his account: making individual thematic appearances perceptible and emphasizing the C-sharp that he regards as an anchor within the tonal progression. Both decisions connect his examination of the score with intended audible features of the performance. The notes document these interpretive intentions without presuming that their realization has been independently evaluated.