Bach: Invention No. 4 in d minor

Hooray for short, two-voice pieces! I like this small little invention. We start with the right hand coming in with the subject with the left hand echoing it starting in measure 3. We quickly move back and forth, each voice playing off the other. The first 18 measures seem to be expositional, as the initial subject is tinkered with slightly. The left hand spends most of the time in accompaniment mode, playing simple quarters over the faster 8ths and 16ths of the right hand. This is then switched as a balance of movement. We have a definitive cadence at measure 18, and move from there into new material. I would consider this section as developmental, as the original material reappears at different points, although changed. We have two distinct things going on here, as each hand has a trill while the other continues the line. This is an effective device to bring out the texture, eliminating some distractions while still sounding busy and suspenseful, we have another cadence at measure 38, returning somewhat to the expository material, but differing slightly as it turns into a terminative function. We do slip through a number of different keys, but we begin and end in d minor, and I believe the main part of the section section is in a minor. This piece feels very cyclical as it continues to ebb and flow up and down in scales over and over.