[carol m]

That's a neat trick, 6string! I'm wondering if Ben is thinking of the Major Triads (and I'm very rusty on these things now) because my old guitar teacher was for Classical guitar and he always based the 'workings of music' etc on the major triads and the circle of fifths. To remember the chords and notes of each, I worked out which were the 1 3 5 of each of the more relevant keys (eg Cmaj is C E G). wrote down the chords as notes on a stave (high-lighting the 135 if you like, but I didn't bother), and then played them over and over as arpeggios - a few repeats of Cmaj, then a few repeats of Gmaj and then Dmaj etc. At the same time you can go through a series of different Right hand patterns. This might sound boring (!) and not encouraging of improvisation or 'real music', but you get to learn where the notes are on the sheet music, the progression around the circle of fifths, where the notes are on the fretboard, and a variety of right hand patterns. If you say to yourself the 1.3.5 notes as you play them, that also gets learned.
I personally soon adapted this to 1 4 5(seven) which sounds better and is generally more relevant to non-classical music, and played the maj keys followed by the related minor

eg. Key Cmaj - C F G7 a few repeats
Amin - Am Dm E7 a few repeats

Gmaj - G C D7 a few repeats
Emin - Em Am B7 a few repeats

Dmaj - D G A7 a few repeats

Amaj - A D E7 a few repeats

and then repeat with a different right hand pattern of arpeggio/picking
Can also be done just with strumming.

If you go through this routine fairly regularly eg at the start of each practice, it warms up the fingers and the brain. It doesn't take long to go through the sequence, and your ear learns to recognise the different progression and 'voice' of each key.
Hope this is useful