I have been working on this chorale for the past few weeks. I consulted a really impressive book by Christopher Czarnecki entitled J.S. Bach: 413 Chorales Analyzed. I think this book is worth a look-through just to see the gigantic collection of analyses that Czarnecki has created, full of his figured bass and chord symbols. My analysis series is meant to go beyond simple analyses and look at the principles of Bach's writing, so that they can be applied to modern composition.
In this analysis of Ach Gott, vom Himmel sieh' darein, I will point out some ways that Bach uses a variety of means to create an unusual (yet convincing) modulation. I will also mention a subliminal relationship between the Phrygian qualities of the melody and harmony.
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