The Well-Tempered Clavier

Reader's Guide

The Well-Tempered Clavier is generally regarded as one of the most important works in the history of classical music. Each set contains 24 pairs of prelude and fugue, arranged in a rising chromatic pattern through all major and minor keys, beginning with C major and ending with B minor. Bach's title suggests he wrote for a 12-note tuning system in which all keys sounded in tune, called a 'circulating temperament' or 'well temperament', as opposed to meantone temperament, which made keys with many accidentals sound out of tune. During much of the 20th century it was presumed Bach intended equal temperament, but modern scholars suggest some form of unequal well temperament instead. Accounts of Bach's own tuning practice are few and inexact, with debate continuing over whether he meant a range of similar temperaments or a single specific solution. The collection influenced later composers and remains a cornerstone of keyboard literature.

Did You Know?

• The modern German spelling for the collection is Das wohltemperierte Klavier (WTK).

Architecture of the Two Books

The Well-Tempered Clavier is structured as two books, each containing 24 pairs of preludes and fugues. The ordering follows a rising chromatic pattern: C major, C minor, C-sharp major, C-sharp minor, and so on through every key, concluding with a B minor fugue. The composer himself framed the work as a resource for musical youth desirous of learning and as entertainment for those already proficient. The title Bach gave in his own spelling, Das Wohltemperirte Clavier, referred to a category of keyboard instruments of his era—harpsichord, clavichord, and organ—though the newly invented pianoforte was not yet part of that family.

A Long Line of All-Keys Ambition

The idea of composing across every available key was not Bach's invention. John Wilson contributed 30 preludes for 12-course lute or theorbo. J. C. F. Other near-contemporaries include Mattheson's 48 figured-bass exercises, Graupner's eight suites in successive keys, and Suppig's Fantasia ranging through all 24 keys on a 31-note enharmonic keyboard. Bach's achievement was being the first to produce a fully worked keyboard collection spanning all 24 major and minor keys.

The Tuning Question

Bach's title points toward a 12-note tuning system in which every key sounds acceptably in tune—a well temperament or circulating temperament. This stood in contrast to meantone temperament, prevalent in his day, where keys heavy with accidentals sounded noticeably out of tune on a 12-pitch keyboard. As an organist, Bach would have encountered meantone-tuned instruments regularly. For much of the 20th century, scholars assumed Bach had equal temperament in mind, the system that became standard after his death and had been theorized for at least a century before his birth. Yet the three most cited primary sources—Forkel, Bach's first biographer; Marpurg, drawing on information from Bach's sons and pupils; and Kirnberger, one of those pupils—offer few and inexact accounts of Bach's actual tuning practice. Modern research has shifted toward various unequal well temperaments, with some scholars suggesting Bach may have used a range of similar systems, adjusted slightly from piece to piece, rather than a single fixed solution.

Title, Rivalry, and a Manuscript Mystery

The title The Well-Tempered Clavier has an intriguing history. The only similar collection actually published in Bach's lifetime was Johann Christian Schickhardt's Op. Despite these near-misses, the Well-Tempered Clavier stands as the first fully realized keyboard cycle in all 24 major and minor keys, a distinction that has cemented its reputation as one of the most important works in the entire history of classical music.