Bach's Code

By Ray Brown

Today's 4:00 request comes from David of Gloucester, RI, who asked to hear Contrapunctus XIV, from The Art of Fugue by J. S. Bach.  It's a fugue that Bach never completed, and the last work the composer wrote.  It starts with a simple theme in whole notes (heard on the cello at the beginning) and, after working through a slow fugue on that subject (after which any other composer would have written a coda and called it a day), he brings in a second, faster-moving theme to create a double fugue.  After developing that for a while, the texture thins and yet another theme enters (that's three now!).  This one consists of four notes: B flat - A - C - B natural. In the German musical alphabet, B flat is known simply as B, while B natural is known as H, which means that the theme is: B-A-C-H.  So, in what he probably knew would be his final work, Bach weaves in his musical signature.  It all adds up to a triple fugue, one of those legendary feats of counterpoint only Bach could have pulled off.

But he still wasn't done!  He was planning on introducing a fourth theme, the motto theme that we hear throughout The Art of Fugue but have not yet heard in Contrapunctus XIV.  After 239 measures of extraordinary counterpoint, though, we never do get to hear it; just as he's shifting gears yet again, with the tenor voice taking off in the eighth-note theme that would lead to the climactic appearance of the motto, the manuscript abruptly ends...  In the words of his son, Carl Philip Emanuel Bach, who edited his father's works after his death:  "At the point where the composer introduces the name BACH in the countersubject to this fugue, the composer died." 



Scholars continue to be divided as to how this should be interpreted. There are those who say that the fugue was never intended to be completed: since The Art of Fugue could be considered a sort of textbook on counterpoint, it's possible that it's up to the student to complete the fugue, which apparently he could if he's been paying attention. In performing this work, the Emerson String Quartet (Bach never specified the instrumentation, so the work has been performed on everything from solo piano to saxophone quartet) has decided to present the work exactly as Bach left it, the viola line hanging in the air, leaving it up to the listener's imagination how it would have ended, or if it's complete as it is. (image:  Wikimedia Commons)

There are several musicians who have attempted to rise to Bach's challenge.  Here's one:



There are also many composers who have used the B-A-C-H theme as a basis for their own compositions, and we'll open today with one of them:  a very un-Bachian Valse-Improvisation based on the theme by Francis Poulenc.