So, I'm learning 'Stray Cat Strut' right now and came across something I'm not sure I understood. I have to say, I've only just begun to learn theory, so maybe that's why.
Anyway, as far as I can tell, the song is in the key of Cm and the intro chords are: Cm - A# - G# - G7.
While the Cm, A# and G# chords are all built from notes that are in the scale, the G7 contains a B, which is not in the scale.
Why is it used then? Could it be, because it's the major 7th, creating tension, striving to resolve etc. or is there another reason?
Also, how does this out-of-scale chord affect the chord progression? Is it: i - VI - V - IV7 ?
Or would you have to write that in a different way then?