The guitar has a hidden geometry that most players sense but never consciously understand: the same note keeps appearing in different places, and moving between strings follows a consistent rule. Getting this rule clearly in your head before you start the course will make everything that follows click into place much faster.
What you’ll get out of this lesson: A clear understanding of how notes transfer between adjacent strings — the five-fret rule and its exception at the G-to-B string — plus the background on how the 12 notes of Western music are arranged on the fretboard.
The 12 notes and how the fretboard is laid out
There are 12 notes in Western music: the seven letter names A through G (the whole notes), plus the sharps and flats in between them. One important thing to notice: there is no sharp or flat between B and C, or between E and F. That means B and C are always just one fret apart, as are E and F. All other neighbouring whole notes are two frets apart. This is the single most useful thing to understand about how the fretboard is organised.
How notes repeat across strings
Every note on the guitar is doubled five frets higher on the string below it — or equivalently, five frets lower on the string above. This is a direct consequence of how the guitar is tuned: the 5th fret of any string sounds the same pitch as the open string below it. So if you know a note on one string, you can find it on an adjacent string by moving five frets in the appropriate direction.
The G-to-B exception
There is one exception to the five-fret rule: between the G and B strings, the interval is only four frets. So if you want to move a note from the G string down to the B string, you go back four frets rather than five. Conversely, moving from B up to G requires going forward four frets. This exception catches a lot of players out — keep it front of mind.
Diagram 2
If you’re going to move it down a string, you’ve got to bring it up five frets. If you want to move up a string, you’ve got to go back five frets and up the string. The only exception being if you’re ever transposing across the G to B string, where it’s four frets.
Taking it further
Once this movement feels natural, you can use it to quickly locate any note you already know in a new position. If you know where F is on the A string, for example, you can immediately find F on the D string (five frets higher, one string lower) and on the low E string (five frets lower, one string higher). This cross-string navigation is a core part of fretboard fluency.
Your homework
Spend five minutes picking any note at random on the fretboard, then finding the same pitch on the string below and the string above. Say the note name out loud each time. Pay special attention to the G-to-B boundary — make a point of crossing it several times so the four-fret shift becomes automatic.