This piece by Kuzmin is an example of Russian late-Romantic piano writing that incorporates traditional forms with a dense, emotive harmonic language. It is distinctive for its use of B minor to evoke a somber, brooding character through intricate polyphony.
At Henle 7 this is a late-advanced work — the technical demands are serious and sustained. The main demands: independent voices that must each sing on their own line; chord voicing — bringing out one note inside a handful of others; and rubato that must breathe naturally without losing the pulse.
Beyond that, expect sharp dynamic and character contrasts held together in one arc, and big chords that need weight without harshness.
At roughly 8 minutes, stamina and memory become part of the challenge — plan practice in sections.
Achieving the correct balance between the deeply expressive melody and the subordinate contrapuntal lines is the primary 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.
Fantasia and Fugue in B minor (Op.18) is rated Henle level 7 of 9 — late advanced repertoire, roughly ABRSM grade 8 and above.
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 Fantasia and Fugue in B minor (Op.18) lasts about 8 minutes.
Fantasia and Fugue in B minor (Op.18) 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 Fantaisie-impromptu by Frédéric Chopin, Asturias (Leyenda) by Isaac Albéniz, Ballade by Edvard Grieg — see the full similar-pieces list on this page.