[No.] 12 [Key] G-sharp minor [Description] 
The prelude is a passacaglia, a form Shostakovich had previously used in the third movement of his Violin Concerto No. 1 in A Minor (Op. 77). The passacaglia motif is counterpointed by one single simple melody. On the contrary, the four-part fugue in 5/4 is a rhythmically adventurous and complex composition that works as a culmination of the first part of the entire cycle.