Chopin's Fantaisie-Impromptu was finished in 1834 and then put away; he never published it, and he left instructions that none of his unpublished manuscripts should be printed. In 1855, six years after his death, his friend Julian Fontana printed it anyway — so one of the best-known pieces he wrote exists against his own wishes. 5:01, with the full piano score on screen, note by note.
Why he withheld it has never been settled
Finished in 1834, put away, never published. Fontana printed it twenty-one years later as Op. 66 — a number Chopin never gave it, assigned after his death.
Why did he withhold it? Nobody knows. One theory is that he heard too much of the finale of Beethoven's "Moonlight" Sonata in it. Another, from the musicologist Ernst Oster, points to a clear resemblance to Moscheles's Impromptu in E-flat major, Op. 89 — published that same year. Both are conjecture; Chopin left no explanation.
There is one more twist. In 1960 the pianist Arthur Rubinstein acquired a manuscript dated 1835 inscribed "Composed for the Baroness d'Este". Rubinstein's reading was that "composed for" meant Chopin had sold it to her outright, and so could not publish it himself. That too is conjecture.
It travelled further still: in 1918 the melody of the middle section had words put to it as "I'm Always Chasing Rainbows", and became a popular song sung in America for decades.
The two hands never line up — and that is the point
The left hand starts first, going round and round, as steady as ripples. Four bars later the right hand joins and starts circling too — but the two are counting differently. Four notes to a beat in the right hand, three in the left; the two layers never line up except once at the top of each beat.
Listening, you cannot fix on which hand is the main one. They slip past each other and cover each other, and the effect is slightly dizzy, slightly hurried — though nothing is actually hurrying.
The middle section changes everything: the speed drops, the right hand becomes one long singable line, the left lays a bed underneath. That is the section that later had words put to it.
Then the circling returns, and at the end the left hand is left alone with a run of low notes while the right holds one very quiet chord high above.
Four sections, and the middle one changes key and breathing
The score marks the divisions itself: a four-bar introduction, then A from bars 5 to 40, B from 41 to 82, A again from 83 to 118, and C from 119 to 138 to finish.
The four-against-three is written into the notation: sixteenth notes in the right hand against triplets in the left, meeting only on the first note of each beat. This is not performer's licence — it is on the page.
Section B moves to D-flat major, which on the keyboard is the same set of black keys as C-sharp minor, respelled from sharps to flats. The tempo marking changes with it, and it is the one stretch of the piece that can slow down and sing.
In the closing bars the left hand runs upward in the lowest register while the right holds still up high. One hundred and thirty-eight bars and three thousand three hundred and seventy-six notes.
Four against three is not counted out — it is practised apart
Most people get stuck on the first thing: four against three. You can work it out arithmetically by dividing the beat into twelve, but it comes out stiff. The usual approach is to practise each hand until it needs no thought, then put them together and let the ear accept that they do not line up.
The right-hand sixteenths need to stay even, especially the second and third of each beat — those are the two that get flattened by the weight of the one before.
The left hand makes four wide leaps per bar and never stops; the bass has to drop and come straight back. By the end your arm knows about it. That is stamina, not technique.
Section B has the opposite difficulty: once it slows, the right-hand line has to sing rather than be struck note by note.
We rate this 5 out of 5.
Also published after he died
Others in the batch Fontana gathered and published: the Waltz in C-sharp minor, Op. 69 No. 2, and a set of mazurkas. Like this one, none of them had Chopin's approval.
For a late work by the same composer that he did approve: the Waltz in C-sharp minor, Op. 64 No. 2.
For the shortest thing here: the Prelude in A major, Op. 28 No. 7 — sixteen bars.
