across the fretboard

fretboard generator

Guitar Fretboard in Depth 

So, what is the correlation between guitar tuning and the guitar fretboard?

This is actually a key point to consider, in order to understand how notes are arranged on the fretboard, as any change in tuning will produce a completely new array. Although there are potentially limitless ways of tuning the guitar, the most useful tuning to know (at least at an initial stage) is the standard one: six strings tuned at the interval of a perfect fourth from each other, except for the second and third strings, which are tuned a major third apart.

Examples: using shell voicings - pdf