A late-period masterpiece, this waltz is haunting, fragmented, and strikingly modern for its time. It strips away the bravura of his earlier works to reveal a sparse, wistful, and highly personal harmonic language.
The challenge is executing the subtle, elusive rubato and precise articulation needed to capture its fragile, ghostly character.
Comparable difficulty and character — good candidates for what to learn next.
Valse oubliée No. 1 (S. 215) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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 Valse oubliée No. 1 (S. 215) lasts about 3 minutes.
Valse oubliée No. 1 (S. 215) 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 Liebestraum No. 3 in A-flat major by Franz Liszt, Ave Maria after Schubert S558 by Franz Liszt, Ave Maria d'Arcadelt by Franz Liszt — see the full similar-pieces list on this page.