Johann Sebastian Bach's '5 Preludes and Fughettas' are charming, concise contrapuntal pieces that demonstrate his genius for melodic invention and imitative writing. These miniatures are excellent for developing keyboard facility and an understanding of Baroque counterpoint.
Requires precise fingerwork and careful attention to the independence of each melodic line.
5 Preludes and Fughettas is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 5.
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 5 Preludes and Fughettas lasts about 6 minutes.
5 Preludes and Fughettas is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.