Busoni's work serves as a synthesis of his neo-Baroque interests and his own late-Romantic pianistic language. It combines the structural rigor of a Bachian fugue with a modern, dense harmonic palette.
At Henle 8 this is concert repertoire: professional-level technique is the entry ticket. The main demands: independent voices that must each sing on their own line; big chords that need weight without harshness; and chord voicing — bringing out one note inside a handful of others.
Beyond that, expect sharp dynamic and character contrasts held together in one arc, and fast passage work that stays light and even at tempo.
At roughly 10 minutes, stamina and memory become part of the challenge — plan practice in sections.
The performer must reconcile the heavy, virtuosic chordal writing with the necessity for clear contrapuntal voicing.
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.
Fantasia, Adagio e Fuga, BV B 37 is rated Henle level 8 of 9 — concert repertoire, roughly diploma level. In the RCM system it corresponds to about level 10.
You should be comfortable at Henle level 8 — meaning you can already play level 7–8 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 Fantasia, Adagio e Fuga, BV B 37 lasts about 10 minutes.
Fantasia, Adagio e Fuga, BV B 37 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 Editions - Liszt: Réminiscences de Don Juan (S.418), BV B 71 by Ferruccio Busoni, Fantasia contrappuntistica by Ferruccio Busoni, Fantasia Contrappuntistica, KiV 256 by Ferruccio Busoni — see the full similar-pieces list on this page.