Bach's "Well-Tempered Clavier" set the example for the creation of Well-Tempered for the first time, and its influence was extremely far-reaching. This collection of music is one of the most important works in piano literature and is known as the "Old Testament" of piano music.

This collection of music is two collections of music composed by Bach for keyboard instruments. The first collection was completed in K?then around 1722 and has a clear teaching purpose. The second collection was compiled in Leipzig in 1740. Each episode has 24 preludes and fugues in 24 major and minor keys. Each prelude and fugue are placed in the same key, but the theme is not connected. The prelude is free in form, and the fugue shows Bach's superb contrapuntal creation skills. The collection of music confirmed the superiority of twelve equal temperaments and further established the Western major and minor modes. It is the highest masterpiece of Bach's keyboard works.