This is a theoretical analysis of BWV 226 by J. S. Bach. It contains information from other writers for theoretical and historical information, as well as original information from the author. Graphs, tables and charts are included. The information is from many perspectives, and includes musical graphs of a Schenkerian nature. Many authors have written of the music of Bach, but theoretical analyses of his choral music are few. The myriad of motives and tonal plans is a treasure box, which is now partially opened.