The clavichord is a keyboard instrument, like the harpsichord, piano, virginal, spinet, and accordion. It is in the class known as the box zither, putting it also in the company of the dulcimer and autoharp. The main division in clavichords is between fretted and unfretted versions.
The clavichord is built in the shape of a rectangle. When the keys are pressed, blades, called tangents, rise to strike the strings above them. The player controls the dynamic by the amount of force used to strike the key, but overall, the instrument is limited in the range of its sound, and cannot play extremely loudly. Because the tangent must be held against the strings and not allowed to bounce off, the touch required for the clavichord is different than for other keyboard instruments.
The clavichord was the favorite instrument of Carl Philipp Emanuel Bach, but though the same sentiment has been attributed to his father, Johann Sebastian Bach, the fact that upon his death Bach senior reportedly was possessed of six harpsichords and no clavichords is thought to render it unlikely. His work, properly called The Well-Tempered Clavier, meaning a piano, harpsichord, or clavichord, has been translated as The Well-Tempered Clavichord, which may be the origin of the idea. Haydn reportedly told his biographer, that although he was living in poverty at as a young man, when he was playing his clavichord, old and worn though it was, he did not envy even the king.
Christopher Hogwood, a specialist in Baroque music, has made several recordings focusing on the clavichord works of famous composers, using eighteenth century instruments, including a clavichord that belonged to Mozart. Clavichord was used by composer John Addison in the music for the 1963 film Tom Jones, as well as being the inspiration for the theme of the television series Murder, She Wrote.