Bach's Well-Tempered Clavier
by Henry Sloan
Sometimes called the Old Testament of piano repertoire, these two books feature some of Bach's most famous, influential, and beautiful works.Johann Sebastian Bach's Well-Tempered Clavier (WTC) is a collection of two books, each of which contains a prelude and fugue for each major and minor key. The two books, published in 1722 and 1742 respectively, represent a substantial milestone in the history of composition. A culmination of technological developments, stylistic variety, and creative brilliance, these books marked the transition from the Baroque era into the Classical era.
A prelude is, as the name suggests, a work written specifically to precede another piece, or set a particular mood. Though preludes in recent centuries have sometimes been standalone pieces, Bach's preludes sought to establish a specific key and mood.
A fugue is a Baroque compositional device where several independent voices imitate a melody (the theme) in a structured way. In the beginning, voices come in one by one, stating the melody. Once all voices have stated the theme, the piece continues on with material based largely around the same theme.
The WTC revolutionized the prelude and fugue genre, proving that simple preludes can put across complex emotions, and complex fugues can lucidly convey beauty. The work also contributed to the popularity of cycles through all the keys. This refers to organizing large works as various pieces with different key signatures. This precedent influenced such works as Chopin's and Scriabin's preludes, and numerous later collections of preludes and fugues.
The technical goal of the WTC was to demonstrate a novel tuning system for keyboard instruments. This so-called well-tempered tuning tuned each note of the instrument such that each key signature (e.g. C major, F-sharp minor), sounded consonant and resonant. The dominant system in Bach's time had been meantone temperament, based around a very simple pattern of pitch ratios. Meantone tuning was designed so that common keys such as C, G, A, and E-flat sounded good, but made less common keys like F-sharp major practically unlistenable.
Well-temperament offered one solution to this problem. It is a type of irregular temperament, where notes are tuned relative to each other in different ways. This effectively distributed the tuning errors of meantone tuning over different keys, so every key sounded good. This has the side-effect of giving each key a unique key color, or balance of tension and resonance.
The tuning system currently used for almost all Western music is twelve-tone equal temperament, which divides the octave into twelve equal parts. This system gives all keys an identical, though slightly imperfect, tuning. Different keys can still have different feelings under our modern system, but mostly due to their effects on the timbre (sound profile) of an instrument.
Check out some of our guided tours through the wonderful preludes and fugues of the WTC. The entirety of both books will eventually be covered, and this section will be updated as they are completed.