This diagram shows all notes of the G major scale between the 2nd and 15th fret. Notes of the G major pentatonic are colored green, except for the root, which is blue. Using each note of the major scale as a tonic yields the seven different modes
If we start playing each mode on the lower E string and try to play without stretching or moving our hand too much, we naturally end up with five different positions: one position starting from each note of the pentatonic scale because in two cases two modes can be played in the same position (Phrygian/Lydian and Aeolian/Locrian).
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