Bach’s Two-Part Inventions: which to learn first, and what they teach you

Nobody has ever come to a first lesson and asked to learn a Bach Invention, and I would not open with one. We start with a piece you already love — that is the whole method, and most of what you need turns up because that tune asked for it.

But with some students the question eventually changes. They can play the thing they came for, they can play the next one, and what they want now is to know how music actually works underneath — why one line answers another, why some music sounds like a mind at work rather than a tune with chords behind it.

That is the point at which I put an Invention in front of somebody. There are fifteen of them, none longer than a couple of minutes, and for a player at that stage they will do more than a term of exercises. They also tend to be met with some suspicion at first, which is fair enough, so it is worth explaining what they are for.

What they are

Bach wrote the Inventions in the 1720s for his eldest son, Wilhelm Friedemann, and put a preface on them that is unusually direct about their purpose. He wanted players to learn to handle two voices cleanly, to develop a singing manner of playing, and — the phrase that gives the game away — to acquire a strong foretaste of composition. The pianist Susan Tomes has the whole foreword, and a walk through the first Invention that shows what he meant by it.

They are not studies in the nineteenth-century sense. There is no mechanical difficulty being drilled. Each one takes a short idea, hands it between the two voices, and follows where it goes. The difficulty is not in the fingers; it is in the fact that your two hands are playing two pieces of music at once and both of them matter.

What they teach that nothing else does

Most beginner and intermediate piano music is a tune with an accompaniment. The right hand is the music and the left hand is the furniture, and a student can play a great deal of it while thinking about only one line.

An Invention will not let you do that. Both hands carry the subject, often within two bars of each other, and if you play one of them as accompaniment the piece simply stops making sense — audibly, in a way even a young student hears immediately.

That is the whole value. The moment a student stops reading two staves and starts hearing two voices is one of the few genuinely irreversible steps in learning the piano. Everything afterwards is easier: Chopin's left hands stop being blocks of chords, a jazz voicing stops being a shape, and sight-reading improves for reasons that are hard to explain but very easy to observe.

Which to learn first

Not the first one. BWV 772 in C major sits at the front because Bach ordered the set by key, not by difficulty, and its running semiquavers are less forgiving than they look — a student who has been promised that this is where Bach begins can come away thinking Bach is not for them.

A more humane order, and the one I use:

1. No. 1 in C, BWV 772 — later than you think. Come back to it once the two-voice habit exists. It is a fine piece and a poor introduction.
2. No. 4 in D minor, BWV 775. This is where I start somebody. The subject is a scale, the texture is transparent, and it moves in a way that carries a student along rather than asking them to generate momentum.
3. No. 8 in F, BWV 779. Cheerful, fast, and enormously satisfying to get up to speed. The one most likely to make a teenager want the next one.
4. No. 13 in A minor, BWV 784. The arpeggiated writing makes the harmony audible rather than theoretical — useful for anyone doing theory at the same time.
5. No. 6 in E, BWV 777. Slower, and the first one that is really about phrasing and the singing tone Bach mentions in his preface. Worth waiting for.

By the time a student has four of them, they can generally read a new one for themselves, which is the point at which my job on this particular front is finished.

How to practise them

Three things, and the first is not negotiable.

Learn each voice separately, and learn it properly. Not "play the right hand through once" — learn the left hand alone, from memory if you can, until it is a piece of music you could sing. Almost all the difficulty in an Invention dissolves at this stage, and almost all the frustration comes from skipping it.

Then play one voice and sing the other. This feels ridiculous and is the single most effective thing I know for this repertoire. You cannot sing a line you have not understood, and you cannot fake attention to a line you are singing.

Take the tempo the counterpoint can bear, not the tempo on the recording. An Invention played at three-quarter speed with both voices clear is a success. Played up to speed with one voice mumbling, it is a failure that happens to be fast.

On ornaments: play fewer than the edition suggests, at first, and start every trill on the upper note. Ornaments in this music are part of the line rather than decoration attached to it — which is a thought I only really understood after spending time with a tradition that never separated the two.

Are they in the exam syllabuses?

Inventions appear regularly in ABRSM and Trinity lists at around Grades 6 to 8, though which ones changes with each syllabus, so check the current one rather than trusting anything written here.

But I would rather they were not learnt for an exam. They are short enough to fit into a student's week for their own sake, and they are one of the few pieces of the repertoire that repay being revisited every few years for the rest of a playing life. I still find things in No. 4 that I missed, and I have been playing it for a very long time.