Position of white dots in guitar fretboard

Question

I was wondering why are the white dots in the fretboard usually placed in frets number 3,5,7,9,12,15,17,19 and 21.

I know that their general purpose is for counting, but what I wonder is why are they placed on precisely those frets, and not different ones (e.g. why is the difference between dots equal to two until 9, and then the next difference is 3?)

Answer 1

The spacing is designed to offer useful milestones on the fretboard. Take the notes on the 6th string (in standard tuning), for example:

• Open (0th fret) is E.
• The F is only 1 fret away, why put a marker on the 1st fret? It's already marked by being the first fret
• The G is on fret 3, so put a marker there.
• The A is on fret 5, which is a perfect 4th from the open string, so it deserves a marker.
• B follows on fret 7, which is a perfect 5th from the open string, so another marked fret.
• Why there's a mark on fret 9, I'll never know, I wish it was on 10 for D instead of 9 for C#
• But you need a marker on 12, for certain - it's the octave!
• The 15, 17, and 19 are just 3, 5, and 7 + 12 (an octave), respectively.

Answer 2

I think it's to signify intervals as much as anything else. The 12th fret is the most obvious - it's the octave. The 3rd fret is pretty obvious because it gives you some general orientation for most open chords. The 5th and 7th frets are valuable because they signify the 4th and 5th interval of the open strings.

Answer 3

Maybe lost to history, the dots are references for the Fibonacci series, which when harmonics are considered, give a pure major chord with octave and perfect fifth redundancies. The dot at the 9th fret marks 2/5ths the string length. The harmonic there is of the 5th partial (the major third) -- this is the one that throws you off.

This is my observation, and it is so easy once seen, that I have little doubt that many people have stumbled across it. Nonetheless, Gibson and Martin guitars had nothing to say about it, and so far as I could see, nothing to see in google searches. THE DOTS MARK THE HARMONICS COMPRISING A PURE MAJOR CHORD.

Are the dots an atavism from pre-equal tempered tuning? In historical paintings of fretted instruments, or in museums, when are the earliest dots seen in their modern location??

string
open = 1 = do
dots
12 = 2nd partial = do (octave over root)
7 = 3rd partial = sol (perfect 5th + octave over root)
5 = 4th partial = do (double octave over root)
9 = 5th partial = mi (double octave + major third over root)
3 = 6th partial = sol (double octave + perfect 5th over root)

Answer 4

Ok, I found other way to explain the ninth fret. When I was starting learning music teacher have shown me solmization sounds (do, re, mi, fa, sol, si); which was most basic major scale; sounds in it are c, d, e ,f, g, a, b(in my country h). And I was thinking how I would mark fretboard if I did it by myself.

First string tuned to e. How to map any sound from these with rule: do not mark adjacent frets? The easiest way is to put a dot between c and d.

• e - 0 fret
• f - adjacent do not mark
• g - first dot
• a - second dot
• b - third dot
• c - adjacent do not mark
• it is easy to remember that fourth dot is between c and d
• d - adjacent do not mark
• e - double dot octave

Answer 5

They are at important intervals: minor third, fourth, fifth, major sixth, octave.

Then they repeat for the second octave: minor third, fourth, fifth, major sixth.