Mozart's Piano Sonata No. 16 in C, K. 545 went into his own thematic catalogue on 26 June 1788 with a note beside it: a little piano sonata for beginners. That same year he wrote his last three symphonies. 4:29, with the full piano score on screen, note by note.
He wrote "for beginners", then came home through the wrong door
From 1784 Mozart kept his own catalogue of works, entering the date, the title and the opening bars. The page for 26 June 1788 records this sonata with the note: a little piano sonata for beginners. It is the most reliable sentence about the piece, and it is in his own hand.
He never published it. It first appeared in print in 1805, fourteen years after his death.
One thing keeps this "beginners'" piece in the musicological literature: sonata form expects the opening theme to come back in the home key at the end, like coming home. This one comes home through the wrong door — the recapitulation brings the first theme back in the subdominant, F major, and only works its way back to C afterwards. Very few mature sonata movements actually do that.
So it is two things at once: one of the most-opened beginner pieces in any piano room, and a textbook exception.
The left hand keeps drawing the same circle
The right hand sings a very square tune while the left turns a four-note circle underneath — low, high, middle, high, then round again. That circle barely stops; it pushes the whole opening along.
In the middle the notes get smaller and thicker, and the right hand starts running all the way up and all the way back down, like someone taking the stairs up and then down again.
The best thing about it is that it never gets loud. No sudden accents, no extreme registers — good to leave playing while you do something else.
Both hands play the same number of notes — and both halves come round twice
The score is seventy-three bars long, but both halves carry a repeat, so played through it runs 146 bars and 2,616 sounding notes — 1,308 in each hand, an exact half and half. For a piece famous for its tune, the lower hand plays not one note fewer, because that circling accompaniment never stops.
The first four bars are written with both hands in treble clef; the left hand moves to bass clef at bar 5. After that the hands keep crossing registers, and the left-hand clef changes fifteen times in all.
Bar 42 is the famous moment: the opening theme returns, but in F major rather than C. It has to travel a while longer before it is actually home.
The shortest note in the piece lasts 0.029 seconds, and the highest note arrives in bar 44.
The hard part is keeping that circle even
We rate this 3 out of 5. The right-hand figures are easy to recognise; the difficulty is keeping the left hand's four-note loop equally light and even all the way through — one heavy note and the right-hand phrase is pushed out of shape.
The clef changes at bar 5 and fourteen more times after that, so reading means getting used to the left hand moving between two clefs; that is where sight-reading usually stalls.
The scale runs in the middle want evenness, not speed.
The other movements, and the rest of the set
K. 545 also has an Andante and a Rondo: Allegretto; both will follow.
For more of one hand holding a single unchanging job: Burgmüller's Arabesque, and Chopin's Prelude in E minor.
