Deriving and naming the chords of the scale C major

This also applies to A minor, D Dorian as they all have all the notes natural ie the keyboard keys white.


Using these seven chords we can play almost all the musical compositions made or not made yet on the universe. We would need to start with bass C if composition is in major key or bass A if in minor key or bass D if in Dorian key.


But it is best to use the real key or scale of a composition as this dictates the atmosphere. For example E minor key.
But the same 1 3 5 7 rule apply.
All we have to do is adding the corresponding flats or sharps that define the key. For example making each F sharp (#F) if the key is E minor.


All music is referenced to bass.


And the names of chords are derived by the intervals (of the notes creating the harmony) with respect to bass.


So here it is:


C major scale:
C D E F G A B C


Chords (derived by the 1 3 5 7 ... rule)


C E G B
C major 3rd major 7th


D F A C
D minor 3rd minor 7th


E G B D
E minor 3rd minor 7th


F A C E
F major 3rd major 7th


G B D F
G major 3rd minor 7th


A C E G
A minor 3rd minor 7th


B D F A
B minor 3rd diminished 5th minor 7th


That's it.


Of Cource there is also bass code 6 for example C E A. But even this can be derived from the 1 3 5 7 9 11 13 rule if we take number 13 with respect to bass. It should end at 15 as this brings us back to C.


Exercise 1:
Try to play Gonna Fly Now - Bill Conti using the above chords.


Exercise 2:
Try to play the introduction of Old and Wise - Alan Parsons Project with these chords.

Note: on both above exercises you will play the music in the original key as these compositions are writen in the key of C major and A minor respectively. Old and Wise continues (modulates) to the key of C minor and bass descends chromatically ie semitone by semitone.


Sources:


The Bach's composition manual:


Bach Bass Rules - Bach, Niedt - Schmidt
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf


Harmony - Piston


Note:
Not sure how it is done but if chord is for example F A C E one instrument (bass for example) can play F, another instrument A, another instrument C, another instrument E. For example trumpets, human voices, strings or combinations of them.