Tune of the Day: Crab Canon by J.S. Bach
This famous piece is part of Johann Sebastian Bach's Musical Offering, a collection of keyboard compositions all based on a single musical theme given to Bach by King Frederick the Great of Prussia, to whom they are dedicated.
Bach didn't give this piece a title; in fact, it was simply labeled “Canon I a 2” in the Musical Offering. It is, however, a retrograde canon, meaning that its two musical lines are horizontally mirrored; in other words, the second line is the same as the first one, but played backwards. The “Crab canon” title emerged exactly for this reason, as crabs supposedly walk backwards (well... in reality they mostly walk sideways, but they are capable of walking backwards as well).
The piece was a major source of inspiration for Douglas Hofstadter's Pulitzer Prize winning book Gödel, Escher, Bach (1979). Notably, one dialogue in the book is written in the form of a crab canon, in which every line before the midpoint corresponds to an identical line past the midpoint.
In order to fit the range of the flute, the present arrangement has been transposed from D minor to G minor.