Saturday, August 18, 2012

How to write a Crab Canon

What's a crab canon?

According to wikipedia:

A crab canon—also known by the Latin form of the name, canon cancrizans—is an arrangement of two musical lines that are complementary and backward, similar to a palindrome. Originally it is a musical term for a kind of canon in which one line is reversed in time from the other (e.g. FABACEAE <=> EAECABAF).

Ever since I read about this in the Goedel, Escher, Bach book by Douglas Hofstadter I've had some fascination with this form of music. I've tried to write some but I usually got stuck after about three notes. In some previous articles I discussed how I created a 5-part canon and a 6-part invention using a technique I have invented (or more likely: rediscovered). Now I have extended this technique to create crab canons and palindrome canons et voila! A brand-new no-sweat, no-tears 4-voice palindrome crab-canon in the somewhat exotic meter of 11/4 appears... (why 11/4? Because I can ;) )

You can hear it on Youtube:

or SoundCloud:

The article explaining the full construction of this piece is available for download here. You may have trouble downloading it with some versions of internet explorer. In that case use chrome or firefox instead.


  1. Technically impressive !
    I wish I knew as much about music theory as you do.
    Although I don't know about solfege I think it is attractive posts.

    1. Hello DoosC, good to see you back :)

      Thanks for the comment. I think you hit the nail on its head by saying that it is "technically" impressive rather than "musically" impressive. It is probably what that distinguishes amateurs like me from masters like J.S. Bach: Bach used all kinds of such tricks in his music, but managed to do so in a way that led to impressive music at the same time.

  2. I was just looking around for something to link to on FB to show others that no, my interest in crab canons (and contrapuntal procedures in general, particularly canons and that Tudor favorite, diminuation) is not a general indication of psychopathy. Then, lo, your site appeared! I think your example is a very good one, and your explanation, excellent. Have you read Allan Atlas' passage on crab canons in his book, Renaissance Music? Because he actually shows how much easier it is to write complex crab canons utilizing 14th century rules that lie outside the, you should pardon the term, canon of modern harmonic relationships.

    Anyway, thanks again. Glad others are interested in this and similar forms, and that you do it so well!

    1. Hello glinka21, glad you've enjoyed the explanation :) I haven't read the book you refer to, but you've made me curious.

      FYI: I've written a number of explanations on writing different types of canons, the latest one being about writing a table canon in 4 voices. All those articles are listed in my blog entry about generating tonal canons using algorithmic composition.

      Have fun on your future musical path.