A mirror fugue is a
fugue
In music, a fugue () is a contrapuntal compositional technique in two or more voices, built on a subject (a musical theme) that is introduced at the beginning in imitation (repetition at different pitches) and which recurs frequently in the co ...
, or rather two fugues, one of which is the mirror image of the other. It is as though a mirror were placed above or below an existing fugue, producing
inversions of each interval in each part, as well as inverting the position of the parts within the texture, so that, for example, the topmost part in one fugue is inverted to produce the lowest part in the other. This is well demonstrated by the two four-part fugues of Contrapunctus 12 in ''
The Art of Fugue
''The Art of Fugue'', or ''The Art of the Fugue'' (german: Die Kunst der Fuge, links=no), BWV 1080, is an incomplete musical work of unspecified instrumentation by Johann Sebastian Bach. Written in the last decade of his life, ''The Art of Fug ...
''.
The two three-part fugues of Contrapunctus 13 exhibit a similar relationship to each other, but this cannot strictly be called a mirror fugue, since the position of each inverted part is not itself inverted in the texture, SAB becoming not BAS, but BSA.
[Boyd, Malcolm. ''Oxford Composer Companions: J.S. Bach'', Oxford University Press, 1999, p. 296]
See also
*
Fugue
In music, a fugue () is a contrapuntal compositional technique in two or more voices, built on a subject (a musical theme) that is introduced at the beginning in imitation (repetition at different pitches) and which recurs frequently in the co ...
*
Mirror canon
The mirror canon (also called a canon by contrary motion) is a type of canon which involves the leading voice being played alongside its own inversion (i.e. upside-down). The realisation from the 'closed' (unrealised) form can be effected by placi ...
References
Polyphonic form
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