Prelude & Fugue No. 10 in E Minor

When Bach first devised the Prelude and Fugue No. 10 in E Minor, its opening Prelude consisted purely of chords—solid in the right hand, broken in the left. It was probably intended as a skeletal structure around which his 11-year-old son, Wilhelm Friedemann, could learn to improvise. In later years, when he was compiling Book I of the 48, Bach clearly decided not to leave anything to chance, and carefully wrote down his own embellishments. The opening of the Prelude now sounds like chamber music, and we can almost imagine an oboe sustaining a beautiful singing line above a simple string accompaniment. At the end of this section, Bach launches without warning into a fast and brilliant “Presto”—also added later. It provides a smooth link with the following movement, the only two-part fugue in the 48. Based on a furious, pattering theme, full of tiny melodic steps (chromaticism), it’s a technical showpiece designed to celebrate the dexterity of the player. About J.S. Bach's Well-Tempered Clavier Book I If we had to choose the most influential of Bach’s works in the centuries since his death, the biggest votes would probably go to the St Matthew Passion and The Well-Tempered Clavier. The epithet “well-tempered” refers to “equal temperament”—a new method of tuning keyboard instruments, which made a wide range of keys available. Bach showed off these possibilities in two books of preludes and fugues in all 24 major and minor keys, which is why the collection is sometimes known as the “48”. Partly drawing on earlier works, Bach completed Book 1 around 1722, and Book 2 20 years later, constantly revising both. He intended the pieces to be useful to players of all types of keyboard instrument.