All keyboard players can use this method of learning chords if you are prepared to play your own bass notes to match the chord.

Keyboards with the Auto-Chord feature cannot use this method because the keyboards computer selects the bass note for the chord you are playing. For example if you play an F6 chord on a keyboard using Auto-Chord the keyboards computer will insert an F bass note or riff based on F6 chord. However, F6 chord is also a Dm7 chord as long as there is a D bass note played. Organ players have the choice to play there own bass notes which means when you have learnt to play F6 you have also learnt to play Dm7. One chord position with the left hand but two chords learnt just make sure to use the correct bass note, F pedal for F6 and D pedal for Dm7.

There are many examples of these chords. I wont list them all but the examples I do list you can work out a lot more for yourself.

Using the above example F6 is also Dm7. There are two ways to look at this. To find the minor chord from the sixth chord we need to know the sixth in the F6 chord. The sixth in F6 is D so we can make Dm7.

Lets check the notes in both chords. First F6:

F, A, C, D. F = Root A= Third C = Fifth and D = Sixth plus an F bass note reinforce or emphasise the Root.

Next Dm7:

F, A, C, D. F =Minor Third A =Fifth C =Seventh and D = Root plus a D Bass (more important this time) to emphasise the Root.

If you dont like the theory then try counting notes from the name of the chord. For example, if we count three semitones to the left from F, you get D or if you count three semitones to the right from D, you get F. So F6 = three semitones left to get Dm7. Dm7 = three semitones right to get F6.

So using one of the above methods C6 is also Am7 dont forget the correct bass notes or pedal notes make the chord what it is.

Using the above method by learning all twelve sixth chords you will also be learning all twelve minor seventh chords or vice versa.