puzzle canons

we're studying puzzle canons in my counterpoint class. they're quite fascinating - i'm told there are puzzle canon books, just like crossword puzzle books. boy, would i like to get my hand on one of those.

a canon is a composition with 2 or more voices. each voice sings the same melody, offset by a few bars or so. take, for example, the tune row row row your boat, or frère Jacques. one person starts to sing, then a little while later, a second person sings the same thing, and the whole thing sounds good together.

a puzzle canon is similar. what happens is that the composer writes out one line of music, a nice singable melody. then to solve the puzzle canon, you take this line and find a way to have it repeat itself on top of itself, with its second version coming in after the first version has already begun. it may stay in its original pitch, or it might need to be transposed by a perfect fourth, or perfect fifth, or by an octave (or maybe something else!). and when the two are heard together, the rules of renaissance counterpoint must be observed - consonants must be heard where expected, and dissonances must be treated properly. musicians were expected to figure this out for themselves, being given nothing more than one line of music and instructions for turning this into a canon by augmenting or diminishing or inverting and transposing.

oooooh, what fun. i've found references to Bach's Musical Offering (BWV 1079) in my internet search for information on puzzle canons. if you haven't yet listened to the Musical Offering, i'd highly recommend it. it's an amazingly interesting set of canons, fugues, ricercars and a sonata based on a bizarre theme given to Bach by Frederick the Great. he's taken the theme, augmented it, diminished it, transposed it, inverted it and written it backwards against itself. what a brilliant man...