Bach Two-Part Invention IV – Harmonic Analysis

When I was younger I was really intimidated by JS Bach and his compositions (I probably still am to some extent). All those sharps and flats, and challenging pieces to play, never mind the overall elitist feeling of classical music and it’s admirers. And the rules and etiquette about playing classical guitar with proper positioning, fingernails and rest and free strokes.

After recently becoming aware of the potential for classical music improvisation, my interest in baroque music has resurfaced. Ted Greene improvised baroque-style music and not only that usually on a Fender telecaster!

Okay back to the analysis. I usually look at the key signature to see what key we’re possibly in – its either the major or the relative minor. Here’s the piece (I suggest you buy this if you’re interested – for guitar something like 15 Two-Part Inventions for Solo Guitar:

Bach Invention 04 a4

First thing we notice is there is one flat, so this would indicate F major or D minor. The melody starts with a D and in the second measure we see a C# so this tells me it’s likely D minor. C# is the raised 7th indicating a harmonic minor scale and also an A chord which is the V chord of D minor (V chord is often major in a minor key, corresponding to raised 7th degree of minor scale). With only two notes it is sometimes difficult to determine the chord, but we can also use the logic of chord movements such as i V and cycle of fourths.

So measure one looks like Dm chord (i), then A chord (V), measure 3 looks like Dm with a D and F on beat 1, beat two is F and A, beat 3 is A and D (3 notes of Dm chord). Measure 4 is back to A7 since we note the C#, G, and A/C# on beat 2. Measure 5 is Dm again with D/F on beat one, A/F on beat 2, D/A on beat 3. Measure 6 is back to A7 with E/C# beat 1, and G/A beat 2. Measure 7 is Dm with D/F on beat 1. Then we go through the cycle of fourths (Gm, C, F, Bb, Edim, Am, Dm) for measures 8 to 15 since we have on the first beat – G/Bb, C/E, F/A, Bb/D, E/G, A/C, D/F). Note the Am instead of A major. Since we are moving into the relative major key (F) we want to weaken the sound of Dm to make the transition more smooth.

From the Dm we discussed in measure 15 we ascend to the iidim chord Edim then down another fourth to Am (v chord) then down a few quick fourths in measure 17 – Dm, Gm, C and then to F major in measure 18 which is a switch from the relative minor key of Dm to F major. Notice the pace slows a bit in measure 17 to accentuate the C chord, which is the V of F major.

Then we alternate between F and C from measures 18-22 until measure 23 where we have a D7 chord. Then D7 in measure 24 (F# and C beat 1), then to Gm (G/Bb) then C7 (E/Bb) then F (see the cycle of fourths?) in measure 26. Note the B natural added to the F chord – this is cancelling the Bb which in essence moves us to the key of C or Am. Since we have a G# in measure 27 it’s likely Am. So in measure 26 the F which would be the I chord in key of F is shifted to a VI chord in key of Am.

That should keep you busy for a while! I’ll let you complete the analysis if you are so inclined.

Other things to note – the use of themes. The intro melody is repeated in the bass in measure 3 and back again in the upper part in measure 5. And this idea is repeated in different areas throughout the piece on different scale tones. And often when one voice is using sixteenth notes the other voice is eighth notes, so the focus can shift between the two voices. Sometimes they both move together in sixteenths which is more challenging on the guitar.

The reason for this analysis is to help us improvise our own Baroque pieces on the fly (use the chord progressions and other ideas), as well as those of you who want to compose your own masterpieces!

If you like this lesson, check out my Baroque Improvisation Course.

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