THIS WILL MAKE THE WORLD BETTER!
Consider a 3-stringed instrument, such as a Cigar Box Guitar. A default tuning might be open Gmaj, or (from head to feet) G--B--D.
My idea is to reverse two strings, therefore: B--G--D. Bar chords are all still major and sound about the same. But instead of a full bar chord, we can use the middle finger to fret only the G--D. The B string is fretted by reaching the thumb over the top of the neck. STILL sounds the same!
But now the thumb can move one fret towards the nut. Voila: a minor chord, because we have flatted the third! So with two easy hand shapes, a person can create all major and minor triad chords.
This also works with 4-stringed instruments if the bottom (i.e. towards the feet) string is an octave of the root/tonic. The key is to have a narrow neck, as in stick dulcimers and most CBGs.
I came up with this two years ago. Now I am sharing with everyone. If you try this and like it, please let me know. And please TEACH OTHERS!
Thanks for listening!
--Patrick "IaNerd" Byrnes, Iowa, USA