Why Fourths Tuning?

A mathematical and practical case for all-fourths tuning as the optimal guitar tuning.

The Premise

Imagine an alien species where everyone plays guitar. They are hyperintelligent. They have worked out every possible voicing, scale, arpeggio, and line on the instrument. Their fretboard knowledge is complete.

One day a young alien comes to the council and says: "I have a new tuning. It requires learning 3x the information, fragments the fretboard into three zones, and creates tons of redundancy. But it makes a few dozen specific voicings slightly easier to finger."

The council asks: "Why would we care about a handful of specific voicings when we already know every possible voicing?" They reject it immediately.

That proposed tuning is standard tuning. The tuning any rational species would start with, the one that treats every string pair identically, is all-fourths tuning. E-A-D-G-C-F. Uniform intervals. Zero special cases.

Standard tuning is not "the" guitar tuning. It is a guitar tuning that became dominant through historical accident. The lute traditions it descends from were optimized for open-string drones, not for the chromatic, position-based playing that defines modern guitar.

The Math: Why 3x?

Standard tuning: E-A-D-G-B-E. Intervals between strings in semitones: 5-5-5-4-5. That single deviation, the G-to-B major third instead of a perfect fourth, is the source of every complexity in standard tuning.

Fourths tuning: E-A-D-G-C-F. Intervals: 5-5-5-5-5. Uniform. Done.

That one-semitone deviation does not create a one-semitone increase in complexity. It creates a multiplicative increase. Here is why.

Triad Example: C Major

C major triads (C-E-G) played across three adjacent strings. Three inversions, four possible three-string sets on a six-string guitar.

In fourths, learn 3 shapes and you can play any C major triad inversion anywhere on the neck. In standard, each shape has 3 variants depending on whether it crosses the G-B break. That is 9 shapes for the same musical content.

Drop 2 Voicings: Cmaj7

Scale it up. Cmaj7 drop 2 voicings have 4 inversions across 4 adjacent strings, giving 3 possible string sets.

4 shapes versus 12. The ratio holds for every chord quality: min7, dom7, half-dim. Every drop 2, every drop 3, every spread voicing.

The General Principle

For any shape spanning 3 or more strings, standard requires up to 3 variants (below the break, crossing the break, above the break). Fourths requires 1. The more sophisticated your playing, the more standard tuning taxes you. This is not opinion. It is combinatorics.

See It For Yourself

Switch between tunings below to see C major on the fretboard. In fourths, the pattern is uniform everywhere. In standard, notice how it shifts when crossing the G-B strings.

The Open Voicing Myth

The most common argument against fourths: "You lose the nice open chords." This sounds reasonable until you test it -so we tested it.

We computationally generated every possible "easy open voicing" on a 6-string guitar for both tunings. The constraints: at least one open string, maximum 3 fretted notes, maximum 4-fret span between fretted notes, anywhere from fret 1 to 12. This covers every physically playable open voicing that a human hand can reasonably reach.

We then ran each voicing through a chord detection algorithm (using the Tonal.js library) to determine if the resulting set of notes matches a recognized chord name. A voicing is "named" if the algorithm can identify it as a known chord (e.g. "Cmaj7", "Dm9", "G7sus4"). Unnamed voicings are still valid, playable combinations of notes; they just don't map to a standard chord symbol.

Both tunings produce the exact same number of physically playable open voicings. Standard names 2.6% more of them as recognized chords. That is the entire empirical basis for the "fourths can't do open chords" claim.

Root Distribution

The more revealing finding is which keys those voicings cluster around.

Standard piles its open voicings into E (5,594) and B (3,905). Not exactly the most universally useful keys.

Fourths distributes across D (4,806), A (4,251), G (3,870), C (3,458), and F (3,412). The keys you actually play in. More even, more practical.

The Survivor Bias Problem

"But standard makes X so easy!" You hear this constantly. An open G chord. A cowboy E minor. The Hendrix chord.

This is survivorship bias. Those voicings are "common" because standard is common, not because they are inherently superior. Generations of guitarists learned those shapes because that is what standard makes easy. Then they wrote songs with those shapes. Then the next generation learned those songs. The cycle reinforces itself.

If fourths had been the default, a different set of equally musical voicings would be "common." The dominance of CAGED shapes is an accident of history, not an inevitable feature of music.

The practical proof: nobody can tell from listening what tuning you are in. Fourths players get complimented on their voicing choices all the time without anyone knowing the guitar is tuned differently. The music doesn't care about your tuning. Only your fingers do.

What Standard Players Already Know

Here is the single most important fact in this article:

The bottom four strings of standard tuning (E-A-D-G) are already tuned in perfect fourths.

Every shape you know on those four strings works identically in fourths tuning. Every bass line, every power chord, every walking bass figure transfers directly.

Switching to fourths doesn't mean starting from zero. It means extending the logic you already know on 4 strings to all 6. An experienced standard player already knows fourths tuning on 67% of their instrument. You don't need to learn new shapes. You need to forget the extra shapes that the G-B break forced you to memorize.

The Design Space

When choosing a uniform tuning, interval size determines the tradeoff between range and playability. Here are the three realistic options:

• Major thirds (4-4-4-4-4): Fully symmetric but too compressed. Notes feel redundant, range shrinks. Only 20 semitones across 6 strings.
• Standard (5-5-5-4-5): Asymmetric. 3x pattern knowledge. 24 semitones. Optimizes for a narrow use case at the expense of the general case.
• Fourths (5-5-5-5-5): Uniform. 25 semitones, the widest range. One shape per voicing type. No redundancy. The Goldilocks tuning.

Allan Holdsworth, widely regarded as one of the most harmonically sophisticated guitarists ever, stated publicly that if he could start over, he would tune in all fourths. The man who could play things in standard that most of us can't even conceptualize looked at the fretboard and concluded the asymmetry was a net negative.

The Honest Cost

I won't sugarcoat this. It took me about six months before I felt truly comfortable. Six months of reaching for shapes that weren't where my hands expected them.

You will temporarily lose your bag of tricks. The memorized licks, the muscle memory, the cliches you reach for when you're not sure what to play.

But here's the thing: that is a feature, not a bug. The discomfort exposes how much of your playing depended on physical patterns rather than musical understanding. When you can't reach for a memorized shape, you have to actually think about what notes you want. Every voicing you relearn becomes something you deeply understand.

Guitar is a lifelong pursuit. Six months of friction for decades of deeper understanding is an excellent trade.

Valid Reasons Not to Switch

1. Deep marriage to existing repertoire. You perform specific arrangements nightly that audiences expect. Re-learning is a real cost. Valid.
2. Informed personal preference. You've evaluated the tradeoffs and simply prefer standard. Completely fine.

Everything else ("it's harder," "I can't play open chords," "it doesn't work for blues") is either mathematically false or a temporary problem that resolves with practice.

But if you've ever felt frustrated by the fretboard, if you've wondered why the same scale pattern works on some string sets but not others, the answer is not that you need to practice more. The answer is that your tuning is working against you.

What Fourths Hub Is Building

The biggest remaining barrier to fourths tuning is not the tuning itself. It's the lack of resources. Standard has 60+ years of chord books and video lessons. Fourths has a handful of PDFs and some forum posts.

That's what this site exists to fix. Comprehensive voicing libraries, interactive fretboard tools, jazz standards with voice leading, practice tools, and scale references. All designed for fourths tuning. All free.

The goal: make the only remaining excuse for not switching be personal preference, not lack of information.