Analysis of Bach's G Minor Fugue (BWV 861)
José Rodríguez Alvira and José D. Sandín
The exposition
This 4 voice fugue is based on a subject (S) presented by the alto:
Recording courtesy of Chris Breemer and Piano Society
The soprano answers with a tonal answer (A) while the alto presents a countersubject (CS) based on motives from the subject transformed by inversion:
The complete exposition:
Recording courtesy of Chris Breemer and Piano Society
They subject may be based on the first two notes:
We can clearly see the evolution of the two notes motive in the following animation:
