The tuning named "Fifourths" is a deeply resonant and notably simplified open tuning for the guitar. As hinted by its original description, it's designed to be intuitive and accessible, providing a rich, droning sonic landscape. It's particularly well-suited for styles that benefit from a full, open-string sound, such as blues, folk, or slide guitar, where its inherent simplicity can unlock creative avenues without complex fretboard navigation.

Technically, this tuning establishes an Open G5 chord across all six strings. The notes from low to high are G1, D2, G2, D3, G3, and D4. This arrangement means that strumming all open strings yields a powerful G5 chord (G, D), which is neither major nor minor but very versatile. The intervals between the strings alternate consistently: the 6th to 5th, 4th to 3rd, and 2nd to 1st strings are tuned a Perfect Fifth apart, while the 5th to 4th and 3rd to 2nd strings are tuned a Perfect Fourth apart. While its name "Fifourths" might suggest a focus solely on fourths, the alternating pattern with prominent fifths creates a strong, foundational harmony.

Open Chords & Possibilities:

• Open G5 Chord: Strumming all open strings produces a full, resonant G5 (G-D-G-D-G-D) chord, perfect for driving rhythms or drone-based music.
• Barre Chords: By simply barring all six strings at any fret, you instantly achieve a G5 chord in the corresponding key. For example, barring at the 5th fret yields a C5 chord. This makes transitioning between power chords very straightforward.
• Two-Finger Power Chords: The consistent G-D interval pattern across pairs of strings (e.g., 6th & 5th, 4th & 3rd, 2nd & 1st) allows for easy formation of power chords and melodic fragments with minimal finger movement.
• Slide Guitar: The open G5 nature of this tuning makes it exceptionally well-suited for slide guitar, enabling players to create full, in-tune chords and melodic lines with ease.

Tuning Notes:

6th String (Low E): G1
5th String (A): D2
4th String (D): G2
3rd String (G): D3
2nd String (B): G3
1st String (High E): D4

How to Tune from Standard E:

• 6th String (Low E): Tune down 9 semitones from E2 to G1.
• 5th String (A): Tune down 7 semitones from A2 to D2.
• 4th String (D): Tune down 7 semitones from D3 to G2.
• 3rd String (G): Tune down 5 semitones from G3 to D3.
• 2nd String (B): Tune down 4 semitones from B3 to G3.
• 1st String (High E): Tune down 2 semitones from E4 to D4.

Important Note on String Gauges: For tuning adjustments that exceed 4 semitones (either up or down), it is strongly recommended to consider using a different string gauge. Large deviations from standard tension can affect intonation, string longevity, and playability. In this "Fifourths" tuning, all strings from the 6th down to the 2nd require significant detuning (4 semitones or more). To ensure optimal performance, prevent string damage, and achieve the best sound, you should consider using a heavier gauge string set designed for lower tunings.