At
Stage Impro in Grenoble their morning 'theory' classes impress on you just how intimate the relationship between chords and scales is. That's why Milleret's present teaching video encourages you to learn the C and G scales (here on a G/C) in
both directions. But if you watch the video through these are actually
part scales.
But as scales and chords "are the same thing" that often doesn't matter. A good example is the pull D7 on a D/G (inner row) helped by a D bass. It is actually all there on push too using (adjacent) notes D F# and A = 1,3,5 of the D scale. Help it with a C bass and you have a full D7, albeit a different voicing.
I purposefully set out to find loads of chords on my kit about 10 years ago and they are really useful. Actually they are fundamental to a Continental style of play. A year or two ago I made up a little excel spreadsheet - ostensibly to find 'scales' on the key. It is utterly ignorant of music theory and you have to list the notes yourself (but they are already entered for most common chords/scales).
It's at
http://chrisryall.net/scalefinder.xls - needs MS Excel to work ("Open Office" macros handle the excel.range() method differently). You have to select the notes of the chord you want yourself using the simplest of music theory.
To construct the "I" chord of a scale you start on note 1, and play alternates 1,3,5,7
To construct its "IV" chord start on note 4, alternates = 4,6,8,10 It's that simple.
Carry on and the notes wrap in the second octave, eg 1,3,5,7,9,11 starting on D is D maj7
9,11 - carry on one more and you've a "fully extended chord", using all 7 notes, hence "scale and chords are the same thing".
So while I must apologise for one of my occasional theory expositions - it's not rocket science. Try the spreadsheet if you have MSoffice installed. It's strength is that is finds
all chords relating to your eg D scale - this including inversions, push
or pull, and those involving bass notes.
It is box independent, indeed instrument independent as simply seeks the notes in the layout you put into the keyboard area. You'll find some chords are partial, but still useful in play. Some of the 'wrong way' chords, or indeed scale fragments will surprise you.
A reversed main scale button in a helper row (E|D on D/G box) is
very useful as it allows virtually full chording on pull. A glighton does the same "Thus endeth the lesson"