The Open Fully Diminished Tuning is a unique and highly specialized guitar setup designed to provide immediate access to the rich, tension-filled sounds of fully diminished chords. As its name suggests, the open strings themselves form a complete diminished 7th chord, making it incredibly easy to explore harmonies and lead lines built around this specific chord quality. This tuning is particularly useful for jazz, classical, or experimental genres where diminished harmony plays a central role, allowing for rapid chord changes and expressive melodic ideas.

Verbal Analysis

Upon strumming the open strings, you'll immediately hear a distinctive, somewhat eerie or suspenseful sound – the unmistakable quality of a fully diminished 7th chord. This means that a single finger barre across any fret (and then possibly shifted by minor thirds) will instantly yield various diminished 7th voicings. The design also lends itself well to open string hammer-ons and pull-offs, creating complex diminished arpeggios with minimal effort. While highly specialized, this tuning can unlock a new realm of harmonic possibilities for adventurous guitarists.

Technical Analysis

The open strings of this tuning are E2, G2, C#4, G3, A#4, E4 (from low E to high E). These notes combine to form an E fully diminished 7th chord (E-G-Bb-Db). The arrangement of these notes across the strings is quite unique, with significant octave jumps and drops:

• The 6th string (E2) provides the root.
• The 5th string (G2) is a minor third above the root.
• The 4th string (C#4, enharmonically Db) is the diminished 7th, an octave and a major second above the 5th string (G2), creating a significant interval jump.
• The 3rd string (G3) is an octave higher than the 5th string, but positioned below the 4th string, creating a descending tritone interval from C#4.
• The 2nd string (A#4, enharmonically Bb) is the diminished 5th, an octave and a minor third above the 3rd string (G3), forming another large interval jump.
• The 1st string (E4) is an octave higher than the root, but positioned below the 2nd string, creating a descending tritone from A#4.

The pattern of intervals across consecutive strings is: minor 3rd (E2-G2), major 10th (G2-C#4), descending tritone (C#4-G3), minor 10th (G3-A#4), and descending tritone (A#4-E4). This unique setup directly facilitates the creation of fully diminished chords by strumming open strings or by barring, and allows for interesting melodic movements due to the repeated notes and specific interval jumps.

Open & Accessible Chords

With this tuning, the primary accessible chord is the E fully diminished 7th chord (E-G-Bb-Db), played simply by strumming all open strings. Due to the symmetrical nature of fully diminished 7th chords (they repeat every minor third interval), you can easily transpose this chord:

• Fretting all strings at the 3rd fret will yield a G fully diminished 7th chord.
• Fretting all strings at the 6th fret will yield an A# (Bb) fully diminished 7th chord.
• Fretting all strings at the 9th fret will yield a C# (Db) fully diminished 7th chord.
• And back to E fully diminished 7th at the 12th fret.

This makes playing diminished chord progressions incredibly straightforward. While other chord shapes will require more adaptation and experimentation, the fundamental diminished harmony is always at your fingertips, ready to be explored.

Open String Notes

• String 6 (Low E): E2
• String 5 (A): G2
• String 4 (D): C#4
• String 3 (G): G3
• String 2 (B): A#4
• String 1 (High E): E4

How to Tune

To achieve the Open Fully Diminished Tuning, adjust your strings as follows from their standard positions. The instructions below indicate the final target note and the required movement to reach it.

• String 6 (E2): Keep as is; no change (0 semitones).
• String 5 (G2): Tune down 2 semitones.
• String 4 (C#4): Tune down 1 semitone.
• String 3 (G3): Keep as is; no change (0 semitones).
• String 2 (A#4): Tune down 1 semitone.
• String 1 (E4): Keep as is; no change (0 semitones).

No special string gauge changes are recommended for this tuning as all adjustments are within a safe range of -2 to +0 semitones from typical standard tuning positions.