That the countersubject has only the limited extent here marked for it, is proved by the fact that the rest of the counterpoint does not systematically reappear later in the fugue as an accompaniment to the subject or answer (see § 298, where the whole fugue is given in score and analyzed).
169. In tonal fugues that modulate to the dominant, the entry of the countersubject is often deferred till after the modulation has taken place. This allows the countersubject to appear without alteration against either subject or answer.
J. S. Bach. Wohltemperirtes Clavier, Fugue 24.
![\new ChoirStaff << \override Score.BarNumber #'break-visibility = #'#(#f #f #f) \override Score.Rest #'style = #'classical
\new Staff \relative f' { \key b \minor \time 4/4
r8 \[ fis^"S" d b g'( fis) b( ais) |
e( dis) c'( b) fis( eis) d'( cis) | bis cis a fis gis2\trill |
fis8.[ \] eis16] fis gis a cis b gis a c \[ fis4^"CS" |
e d cis b ~ |
b8 ais b4 ~ b16 cis d e fis g b, ais | d2 \] }
\new Staff \relative b { \key b \minor \clef bass R1*3
r8 \[ b^"A" a fis d'( b) e( dis) |
a( gis) f'( e) b( ais) g'( fis) |
eis fis d b cis2 | b16 \] s16 s8 s4 } >>](http://upload.wikimedia.org/score/o/k/okv5pyqnuft7wtp3xjmf13516m1ax4k/okv5pyqn.png)
This subject is quoted in some text-books as a particularly difficult one to answer. There is, however, no real difficulty here, if we remember our rule (§ 121), that the modulation must be regarded as taking place as soon as possible. Here it cannot be till after the fourth quaver, because G natural does not belong to the scale of F sharp minor; but from the fifth note of the subject all is regarded in its relation to F sharp minor, and answered exactly by the corresponding notes in relation to B minor, and the whole countersubject is distinctly in the latter key. Notice the curious, and doubtless accidental, resemblance of this countersubject to that of the fugue in E minor, quoted in § 168.
