2.1The harmonic skeleton

A common opening progression is:

Cm7 → F7 → B♭maj7 → E♭maj7

then:

Am7♭5 → D7 → Gm

That is the heart of the tune.

In Roman numerals relative to B♭ major:

ii → V → I → IV

then moving into G minor:

iiø → V → i

This is already a complete theory review.