The CAGED system is a methodology which can be used to learn every note on the fretboard and just about any scale. Its name is an acronym for the five basic chord shapes which form the basis of the system: Start by looking at the octave shapes formed by the Root Notes of each of these chords. Marked 'R' on the diagram below.
By removing all of the notes except for the octave shapes, we can see these patterns more clearly. Note that what we are left with are all the possible ways of fingering movable OCTAVE PATTERNS.
Now if we arrange these shaped to form the word 'CAGED' we are able to chart every note on the entire fretboard.
Try it - start by playing the pattern above, then try this technique with other some new starting points. If you don't already know all the notes on the fretboard this is a great way to learn them.