Walter Niemann was a prolific composer of descriptive piano music in the early 20th century. This piece reflects the 'salon' aesthetic with a focus on charm and simple harmonic beauty.
At Henle 4 this is an intermediate piece that expects secure technique and real attention to phrasing. The main demands: a waltz lilt that needs charm and a flexible left hand; chord voicing — bringing out one note inside a handful of others; and careful pedaling — clarity depends on the foot as much as the fingers.
The primary challenge is to execute the waltz accompaniment with grace and consistent timing.
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.
Erinnerungen (Op.9) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 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 Erinnerungen (Op.9) lasts about 4 minutes.
Erinnerungen (Op.9) 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 Ein Spätsommertag by Walter Niemann, Die Wohnung des Glücks by Walter Niemann, Butterfly by Walter Niemann — see the full similar-pieces list on this page.