Kirnberger was a pupil of Bach and his fugal works are strict exercises in contrapuntal mastery. This piece provides a rigorous look at the formal constraints and techniques of high Baroque keyboard writing.
At Henle 4 this is an intermediate piece that expects secure technique and real attention to phrasing. The main demands: independent voices that must each sing on their own line; fine finger independence within the hand; and ornaments that need to sound effortless, not squeezed in.
Beyond that, expect precise articulation — the difference between crisp and blurred is the piece.
Ensure the subject is clearly projected in all voices through precise articulation.
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.
Dreistimmige Fugue, EngK 31 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 Dreistimmige Fugue, EngK 31 lasts about 3 minutes.
Dreistimmige Fugue, EngK 31 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 Dreistimmige Fugue by Johann Philipp Kirnberger, Allegro in D major by Johann Philipp Kirnberger, Courante in A-flat major, EngK 75 by Johann Philipp Kirnberger — see the full similar-pieces list on this page.