Formal Analysis of J.S. Bach's Two-Part Invention No.8

 J.S. Bach's Two-Part Invention No.8 is in F major, and in 3/4 time.  The piece contains 34 measures.  The range is from C2 to C6.  There are only 3 dynamic markings in the entire piece: forte in measure 1, piano in measure 12, and crescendo in measure 19.  The structure is strictly two-voice counterpoint - the only chord, F Major, appears in the final bar of the piece.  

The structure of the first 11 bars is a classic example of Shoenberg's "musical sentence." It begins with the presentation.  The first 2 measures contain the basic idea as the F major chord is outlined.  This is followed by 2 measures of its varied repetition, which outlines a first inversion F major chord.  Throughout this presentation, the voices create an imitative canon as each measure-long phrase is repeated successively between the two clefs. (For example, in measure 1 the right hand has F-A-F-C-F, and in measure 2, the left hand has the same pattern of F-A-F-C-F, with identical rhythms, one octave lower.)   Then, in the 5th measure, the two voices meet up rhythmically, and remain a 14th apart for two bars.  This second phrase can be called the continuation.  It, however, lasts for 7 bars.  In 4 bars it drives the music to a temporary, and imperfect cadence; in beat 1 of measure 9, the piece reaches F major again, with A in the soprano.  The sentence is henceforth lengthened with 3 measures of harmonic acceleration that drives the piece to a G Major chord (the secondary dominant of C) and a modulation into the dominant key of C Major.  This is an elision cadence.  It simultaneously marks the end of the exposition and the beginning of the development.

The development begins in measure twelve.  It begins with the same imitative pattern as in measure one, except completely reversed - the key is C instead of F, the dynamic marking is piano instead of forte, and the leading voice begins in the left hand, rather than in the right. The basic canon is expanded upon in the development.   In the first 11 bars, each one bar phrase is repeated immediately and successively in the opposite hand.  However, in many cases (m14-15, 18-20, 21-23, 24-25) the phrases in each voice are expanded into 2 bar or 3 bar phrases, which are not always repeated exactly in the opposite hand.  In these situations, the melodic idea is furthered.  In measure 15 a "pedal A" motif is introduced, and repeated in other keys, in both hands, throughout the development.  This can be considered a variation on a previously introduced motif.  In measure 5, the right hand plays F-A-G-A-F-A-G-A-F-A-G-A; in measure 15, the right hand plays C-Bflat-C-A-C-A-Bflat-A-C-A-A-A.  The pattern has been altered but it retains the idea of returning to one note, on the up beat.  Another expansive idea is the descending arpeggio pattern, introduced in measure 21.   This can be considered a variation on the ascending arpeggio pattern that exists throughout the piece until this point.  The new pattern remains in the left hand for 3 bars, then the right for 2 bars, and finally the left for 1 more bar.  In the last bar of descending arpeggios, the motif from the continuation in measure 5 is reintroduced.  This can be called the recapitulation.  The remainder of the piece, m26-34 is identical to m4-12 in rhythm and pattern.  The only way in which it is varied is the tonality.  The first occurrence of this pattern drove the piece to the dominant, however, this instance functions to drive the piece to the tonic, and to the final perfect authentic cadence.

META-CRITIQUE

 My insecurity about the chord structures takes away from the critique, as I don't offer any information about exact progressions.  Additionally, at times when writing the critique, I found myself unsure of how to convey exactly what I wanted to say.  This can be attributed to my own personal level of knowledge, and how many musical terms I am acquainted with.  For example, I was not sure if I could use the sonata form terms (exposition, development, and recapitulation) to describe J.S. Bach's 34 bar invention.  Instances like this may have left my critique feeling a little messy and unclear.

The critique may not be completely objective.  This, again, can be accredited to my uncertainty in how to use terms and what terms to use.  I may have used terms that convey my feelings about the piece instead of 100% pure syntactical fact.  Also, I was unsure whether or not I was supposed to have access to the sheet music of the piece.  Perhaps then, my meta-critique is that I, the author, am a student who is still in the process of learning how to structure a formal analysis.