A triad is a 3-note chord — root, third, and fifth — built by stacking thirds. Harmonizing a major scale gives 7 triads, one per scale degree, in the fixed quality pattern major, minor, minor, major, major, minor, diminished (I ii iii IV V vi vii°).

Takeaways: These are the chords that naturally belong to the key. The third sets major vs minor; the fifth gives the diminished its tension. Playing them on just 3 adjacent strings keeps them compact and movable — tap a card to hear it, or the tab strip to run all 7.

The 5 open chord shapes — C, A, G, E, D — can be barred and moved anywhere on the neck. Together they tile the entire fretboard, giving you 5 ways to play any major chord.

Takeaways: The shapes always follow the order C→A→G→E→D going up the neck. R = root, 3 = major third, 5 = perfect fifth. When improvising, target these chord tones to sound melodic over changes. Each shape also maps to a pentatonic scale position.

A map of all 12 keys arranged by relatedness. Adjacent keys share 6 of 7 notes. Clockwise = up a fifth (dominant), counterclockwise = up a fourth (subdominant).

Takeaways: The I, IV, V chords of any key sit next to each other on the circle. Inner ring = relative minor (same notes, different feel). Sharps increase clockwise, flats counterclockwise. Use adjacent keys for natural-sounding key changes.