Definition

• A canon is a style of contrapuntal (counterpoint) music where two melodies of the song are imitations of each other. Counterpoint music is music that has two or more distinct melodies. There are two basic melodies in a canon, the leader and the follower. The follower imitates the leader and can do so in different ways.
  
  

Requirements

• A canon has three distinct qualities that make it a canon: the follower has to begin after the leader, the follower must replicate the leader’s melody and if the leader changes its initial melody, the follower must also change.
  
  

Types

• The follower can duplicate the leader’s melody by playing an octave above or below, starting on a different pitch, playing the melody backwards (retrograde), playing at a different speed (proportional canon), moving in contrary motion or playing exactly what the leader plays. When starting on a different pitch, the follower either imitates the melody so as to stay in the same key or becomes a transposition into another key (mirror canon). When the follower is imitating the leader in the same key, the follower’s intervals between notes are slightly different from the leader's. Contrary motion is the progression of both the leader and follower using the same note intervals, but in opposite directions.
  
  

Composing

• When canons were first written, composers would hand the players the leader’s melody with some sort of notation to tell them how to accompany the leader. There is a style of scoring a canon where the composer purposefully tries to hide that he has written a canon. Johann Sebastion (J. S.) Bach was well known for doing this. However, he would include clues in his scores to help players decipher the canon.
  
  

Examples

• Perhaps the most widely known canon is Johann Pachelbel’s “Canon in D.” It’s commonly heard at graduations. Good examples by J. S. Bach for the different styles of canon are “Fourteen Canons on the Goldberg Ground,” which utilizes contrary motion and retrograde canons; “Goldberg Variations,” which utilizes unison, octaves and other intervals; and “The Art of the Fugue,” which utilizes the proportional canon.