The Art of Fugue - Instrumentation

Instrumentation

Manuscript copies of the Art of Fugue, as well as the first printed edition, use open scoring, where each voice is written on its own staff. This has led to the assumption that the Art of Fugue was an intellectual exercise, meant to be studied and not heard. However, musicologists today, such as Gustav Leonhardt, agree that the Art of Fugue was probably intended to be played on a keyboard instrument (and specifically the harpsichord). Leonhardt's arguments included the following:

1. It was common practice in the 17th and early 18th centuries to publish keyboard pieces in open score, especially those that are contrapuntally complex. Examples include Frescobaldi's Fiori musicali (1635), Samuel Scheidt's Tabulatura Nova (1624), works by Johann Jakob Froberger (1616–1667), Franz Anton Maichelbeck (1702–1750), and others.
2. The range of none of the ensemble or orchestral instruments of the period corresponds to any of the ranges of the voices in The Art of Fugue. Furthermore, none of the melodic shapes that characterize Bach's ensemble writing are found in the work, and there is no basso continuo.
3. The fugue types used are reminiscent of the types in The Well-Tempered Clavier, rather than Bach's ensemble fugues; Leonhardt also shows an "optical" resemblance between the fugues of the two collections, and points out other stylistic similarities between them.
4. Finally, since the bass voice in The Art of Fugue occasionally rises above the tenor, and the tenor becomes the "real" bass, Leonhardt deduces that the bass part was not meant to be doubled at 16-foot pitch, thus eliminating the pipe organ as the intended instrument, leaving the harpsichord as the most logical choice.

The fact that it is playable on a keyboard at all is evidence for some that this was Bach's intended instrument, as it is not possible to play most of his ensemble pieces on a keyboard instrument.