Chopin's Fantaisie-Impromptu is one of the most beloved works in the repertoire, famous for its 'four-against-three' polyrhythm. The piece is framed by a tempestuous opening and conclusion, contrasting with a serene, lyrical middle section.
At Henle 7 this is a late-advanced work — the technical demands are serious and sustained. The main demands: polyrhythms that have to lock together without sounding mechanical; fast passage work that stays light and even at tempo; and rubato that must breathe naturally without losing the pulse.
Beyond that, expect a true singing tone, with the melody floating above the accompaniment, and continuous sixteenth-note figuration that must ripple, not chatter.
Mastering the polyrhythm between the left-hand eighths and right-hand sixteenths is the essential technical hurdle.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Lesser-known works by the same hand, at a comparable level.
Fantaisie-impromptu (Op.66) is rated Henle level 7 of 9 — late advanced repertoire, roughly ABRSM grade 8 and above. In the RCM system it corresponds to about level 10.
You should be comfortable at Henle level 7 — meaning you can already play level 6–7 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Fantaisie-impromptu (Op.66) lasts about 5 minutes.
Fantaisie-impromptu (Op.66) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Étude in G-flat major, No. 5 by Frédéric Chopin, Ballade No.2 by Frédéric Chopin, Fantaisie-Impromptu in C-sharp minor by Frédéric Chopin — see the full similar-pieces list on this page.