Ignaz Friedman's take on the Bach chorale shows an early 20th-century approach to historical forms. It is marked by a sophisticated harmonic palette and idiomatic keyboard layout.
At Henle 6 this is an advanced piece that assumes fluent technique and rewards mature interpretation. The main demands: independent voices that must each sing on their own line; chord voicing — bringing out one note inside a handful of others; and precise articulation — the difference between crisp and blurred is the piece.
Beyond that, expect rubato that must breathe naturally without losing the pulse.
Developing the capacity to balance complex counterpoint with a personal, expressive rubato is essential.
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.
Choralvorspiel 'Wachet auf, ruft uns die Stimme' is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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 Choralvorspiel 'Wachet auf, ruft uns die Stimme' lasts about 5 minutes.
Choralvorspiel 'Wachet auf, ruft uns die Stimme' 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 Chorale Prelude and Fugue on „O Traurigkeit, o Herzeleid“ by Johannes Brahms, Ciacona in D minor by Johann Pachelbel, Chorální fantasie, JW 8/4 by Leoš Janáček — see the full similar-pieces list on this page.