When I introduce a student to chord chart reading, one of two things always happens. Occasionally, the student looks at me in bewilderment and is very confused. I usually attribute this to overanalyzing. Learning music theory is very important to a musician, but I think that comes after using music theory.
Think how we learn to speak our native language. My parents did not place a dictionary in my crib or drill me with flash cards to learn vocabulary words as an infant. They said simple sentences to me, and I learned to mimick--probably saying one word such as, "potty" or "bottle." Eventually my vocabulary grew even though I didn't realize I was learning a language. Baby's soon say, "Mama" or "Daddy," "bird" or "kitty." My language grew as I grew and my one-word pre-sentences became more complete sentences. "I am hungry." "I have to go potty."
The ii-V7-I progression is very common in jazz and pop music. It is really just a small alteration of the very common classical progression, IV-V7-I. Last month, I wrote about using the chords of that progression in different ways including turning it into the blues progression to allow a student to "get off the page" and improvise.
When we change the IV chord to ii, our progression works essentially the same and we find this progression in countless jazz songs.
This is where learning the progression by sound and feel is more important than analyzing and when introducing this progression. I ask the student to simply play the notes as I give them and I give them a pattern of II-V7-I with good voice leading. Generally, I'll voice it with the third on top of the II chord and leave the 5th out and putting the minor 7th in the chord with my thumb. Then, I'll let the third become the 7th of the V7 chord and use the root and third, again leaving out the 5th. My thumb lowers 1/2 step to the third and the root jumps. Then, we move back to the I chord with the third on top, major 7th in the middle, and root on the bottom. Again, we skip the unimportant fifth of the chord to have a nice voicing. It looks like this:
We then create a progression of continuing ii-V7-I's. The third and seventh of the CM7 chord can be lowered 1/2 step each to create a C minor 7th chord which becomes the II chord to go to Bb which becomes the ii chord to go to Ab and so forth. It can be never-ending.
Students can learn the progression, develop some muscle memory, and learn to easily recognize the pattern in pieces. It is a fun exercise, but only if the student just imitates and doesn't over-analyze or over-think. The student who frees themself to learn and internalize this simple progression will make tremendous steps to moving forward in their ability to express and play the piano.