All was going well until section 25’22s on the video, regarding measure 4 of The Days of Wine and Roses.
Why is the newly improvised and inserted Am7 chord (inserted for beats 1+2), the related ii chord of D7?? I can see that its a dominant motion resolving to D, but wouldn’t Em7 be the related ii chord here?
This is confusing to be sure. It confused me when I was learning this.
There are (2) different types of ii chords you need to think about:
1) The ii chord in the key would be the 2nd diatonic chord in the key. So key of C, that would be D minor.
then there is…
2) The RELATED ii chord. Remember the D7 here is really a V7 chord. So the related ii chord is the chord that goes along with that D7. Think of it like a family, the D7 is V, well what is I? The I chord would then be G. So what is ii? That is A minor.