BWV 663a is a variant or related version of Bach's powerful chorale prelude, BWV 663. It retains the piece's intricate contrapuntal texture and emotionally charged character.
Students must focus on precise execution of the rapid figuration and careful voicing of the melodic lines.
Allein Gott in der Höh sei Ehr (BWV 663a) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 7.
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 Allein Gott in der Höh sei Ehr (BWV 663a) lasts about 4 minutes.
Allein Gott in der Höh sei Ehr (BWV 663a) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.