Guitar Notes on A String (5th String)
The "Given" Root
The A String (5th String) is the second most important string for rooting chords. If you play a standard Power Chord or Minor Barre chord, the root note is likely here.
Landmarks
3rd Fret: C (Root of C Major)
5th Fret: D (Root of D Major shape)
7th Fret: E (Octave of the low E string)
Memorizing the A string doubles your chord vocabulary instantly.