Black Key Mazurka is a stylized Polish dance piece utilizing the characteristic rhythms of the mazurka. Its musical identity relies on the interplay between the triple-meter dance feel and darker minor-key harmonies.
Practice the left-hand rhythmic lilt common to the mazurka style to support the right-hand phrasing.
Comparable difficulty and character — good candidates for what to learn next.
Black Key Mazurka 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 Black Key Mazurka lasts about 4 minutes.
Black Key Mazurka 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 'Valse' for Album des Six by Francis Poulenc, Caledonian Market by Poldowski, Bacchus by Victor Alphonse Duvernoy — see the full similar-pieces list on this page.