This brief work by Schubert demonstrates his mastery of strict formal structures in a pedagogical context. It is distinguished by its clean, linear texture and typical Schubertian melodic charm contained within a compact form.
The player must ensure rhythmic precision in the imitation to prevent the lines from blurring.
Canone a sei (D.873) 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 Canone a sei (D.873) lasts about 1 minute.
Canone a sei (D.873) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.