Two-Part Invention No. 1 (C major, BWV 772)

Background

Bach wrote fifteen two-part Inventions (BWV 772–786), together with fifteen three-part pieces he called Sinfonias, as teaching music. Early versions appear in the Clavier-Büchlein he began in 1720 for his eldest son, Wilhelm Friedemann. In 1723 he made a fair copy of the whole set and gave it a title page explaining its purpose. In short, the pieces were meant to teach players to handle two (and then three) independent parts cleanly, to show how a good musical idea can be found and developed, and above all to help them acquire a singing style of playing along with a taste for composition.

Invention No. 1 in C major shows that method in its purest form. Almost everything grows from the little motif heard in the first bar: seven quick notes and then four slower ones. Bach hands it from one hand to the other, moves it to new keys and even turns it upside down. It is a classic first step into counterpoint, music in which two melodies play at once.

How to practise it

The right hand starts alone. After a sixteenth-note rest it plays the motif, then four eighth notes. Half a bar later the left hand enters with the same motif an octave lower, so the two hands overlap like a conversation.

Learn the motif until you can play and sing it in your sleep. Every time it returns, in either hand, you will recognise it. Finding and marking each appearance in pencil is a good first job.

In bar 3 Bach turns the motif upside down: where it went up, it now goes down.

A practice plan that works for most players:

1. Each hand alone, two bars at a time, slowly enough to play with the same fingering every time. Decide your fingering on day one and write it in.
2. Sing one hand while playing the other: the quickest way to hear both lines.
3. Hands together at about half speed (40 beats a minute), two bars at a time.
4. Join sections, then raise the tempo through 56 and 68 to the full 80.

A common approach to articulation is to play the sixteenth notes smoothly and the eighth notes slightly detached. Whatever you choose, keep it the same every time the motif appears, so the listener can follow it from hand to hand. Balance matters too: neither hand is the accompaniment. When one hand has the motif, let it come forward slightly while the other answers.

If you lose your place in bars where both hands have sixteenth notes at once, such as bars 7 to 10, go back to singing one line while playing the other.

The piano finger numbers guide explains how to write and read fingering like the numbers above.