canon

Piece or passage of contrapuntal music in which one voice repeats the part of another, like an echo. The first vocal or instrumental part begins with the melody and is followed soon after by the second part imitating that melody note for note (though often starting on a different note and keeping the intervallic distance throughout). This can go on up to five or six voices. The second part may follow at half a bar, one bar, two bars, or any other distance the composer chooses. Many examples of canon can be found in the fugues of Johann Sebastian Bach. Canon is called ‘stretto’ when used in a fugue.

Canonic variations may also introduce a difference in starting pitch between the voices. This can make it difficult to decide what key the music is in. The fugue is the most highly skilled of these variations. The main feature of the beginning (exposition) of a fugue is that all the parts or voices (so called whether the fugue is vocal or instrumental) enter one after the other, strictly imitating each other. The fugue has been written by composers since 1600. Johann Sebastian Bach is the undisputed master of the fugue and examples of his work are The Art of Fugue (published 1751) and The Well-Tempered Clavier (1722-40). Other major fugue composers include Dietrich Buxtehude, who Bach admired greatly.