Bach composed the Canonic Variations on this famous Christmas Hymn to be admitted to the “Society of Musical Sciences”. They demonstrate his virtuosic grasp of different fugal and canonical techniques, but at the same time, this is music of great beauty. The material used in the various canons is based on the chorale melody and at certain points Bach also incorporates the B-A-C-H motive
The Canonic Variations survive in two versions. The original edition of 1747/1748 and an autographed copy which Bach added to the “Great Eighteen” Chorale Preludes. The main difference being the order of the movements.
I prefer to play the variations in the order of the original edition as the final variation includes four canons where the chorale itself is used in contrary motion at the sixth, the third, the second and the ninth. At the end Bach introduces the voices in diminution in both normal and contrary motion.