|Book 1 - No. 10 - E minor - Fugue|
With only two voices, this fugue's texture and even its whole nature is distinct. It is the only two-voiced fugue in the entire Well-Tempered Clavier. With only two voices, it is generally much easier to be aware of the full counterpoint: it is a holiday from the more athletic concentration Bach often demands. Relax. Go for a ride. The subject is a thrill, the pace brisk, the motion practically perpetual. Two rockets take off and intertwine in a fantastic parabola of figuration. With only two voices, would one dare to have them state the subject simultaneously, to enter in parallel? Bach plays with our expectations here. He leads to that obvious possibility at least twice. But just as the parallel entry is about to occur, one of the voices darts off into the countersubject. A brilliant feint, a dodge, a musical delight.
The texture, the brevity and even the highly motivic character of the subject give this fugue the feeling of a two-part invention. With only two subject entries, the exposition is short. With only two voices, a mere 8 subject entries total and a reasonable percentage of episode, this fugue lacks the density and the saturation of the other fugues, again, making it feel like a "lighter" invention. With only two voices, the dialog is a tight back and forth rather than a cycle among voices.. As either invention or fugue, it is a wonderful composition.
The fugue structure is compact, tightly organized, startlingly symmetric and regular, strongly balanced between subject, countersubject and episode. Siglund Bruhn's diagram vividly reveals these qualities and shows us a generally inexpressible gestalt that frequently occurs in mathematics, software design and music: elegance.
Shostakovich also provided only one two-voiced fugue among his 24 fugues of Op. 87. While his is a jubilant study in the parallel major, it feels intimately related to this fugue. See Op. 97 No. 9 in E major.