It’s very important before we set out on our adventure that we are clear on what I like to call the ‘guitar pitch axes’ (pronounced ax-ees, the plural of axis). An axis is an imaginary line through the middle of something.
On the guitar fretboard we have two axes. We can move along a horizontal axis (towards the guitar body or the headstock) or a vertical axis (towards the floor or the ceiling).
Remember: On the horizontal axis, 'up' is towards the body and 'down' is towards the headstock. On the vertical axis, 'down' is towards the floor and 'up' is towards the ceiling.