In lesson 41 you learned to create scale tone 7th chords by choosing a bass note and using the triad two degrees ahead on top of the bass note. The same principle can be applied to creating 9th chords. For example, if you place an Em7 chord over a C bass note, the result is a CMaj9 chord as shown in the following diagram. The example which follows uses this method to create a II V I progression in the key of C where all three chords add up to 9ths