Tonalities

There are essentially seven tonalities or chord families:


From Major tonal center:
[ @-7 | %7 | !M ]

Minor (subdominant) : @-7
D-, D-7, D-9, D-11, D-13, etc

Dominant : %7
G7, G7(SUS), G7(s11), G9, G13, etc

Major (tonic) : !M
C, C6, C6/9, CM7, CM7(s11), CM9, CM13, etc


From Minor tonal center:
[ @-7(b5) | %7(ALT) | !m ]

-7(b5) aka ø "half-diminished" (subdominant) : @-7(b5)
B-7(b5), B-9(b5), B-11(b5), etc

7(ALT) (altered dominant) : %7(ALT)
E7(ALT), E7+, E7(s11), E7(b9), E7(b9SUS), E7(b13), etc

m (tonic minor) : !m
A-, A-6, A-6/9, Am, Am7, etc


From Passing Chord Dominant:
[ !M | b@º7 | @-7 ]
[ @-7 | b@7(s11) | !M ]

º7 (diminished) : b@º7
Dbº, D¢º7, D¢º7(M7), A7(b9)/Cs etc

7(s11) (tritone sub) : b@7(s11)
Db7(s11), etc


Chords of the same family are largely interchangeable, given context. i.e. any type of Major chord variation can fulfill the tonality for any Major chord symbol.

This means you only need to learn seven chords to start playing any tune!

For guitar, learn one shape each on E & A string roots for better navigation of the neck.

For piano, there are what Mark Levine calls 'A' & 'B' voicings. 3679 & 7936 (more on voicings later).

A great exercise to get into this is to practice major and minor 2-5-1 cadences with some passing chords as described with the chord progressions above.