This unique and resonant guitar tuning, famously used by Ani DiFranco in her song "Grey" from the album "Revelling and Reckoning," offers a distinct sonic landscape. It's often referred to as C G C G G G, reflecting its open string notes.

Verbal Analysis

This tuning immediately creates a powerful, drone-like quality, particularly due to the three lowest strings all being tuned to G. This provides a deep, resonant foundation that's excellent for percussive playing, intricate fingerstyle, and creating a wall of sound. The presence of C on the third and first strings introduces a suspended fourth (sus4) feel against the dominant Gs, lending the tuning a slightly yearning or open quality rather than a straightforward major or minor tonality. It's a tuning that encourages experimentation, allowing for rich textures and complex rhythmic patterns to emerge from relatively simple fretboard shapes. The open Gs serve as a constant pedal tone, grounding any melodic or harmonic explorations.

Technical Analysis

• Open String Notes: G2 G2 G2 C4 G3 C4.
• Intervals from Lowest G: The tuning presents intervals of Root (G), Root (G), Root (G), Perfect 4th (C), Root (G), Perfect 4th (C).
• Chordal Implications: Strumming the open strings produces a rich Gsus4 chord (specifically, G-G-G-C-G-C) or can be interpreted as a C/G chord (C major with a G in the bass, emphasizing the 4th). This sus4 harmony is central to the tuning's character.
• Movable Shapes:
  • Barre Chords: A full barre across all strings at any fret will create a movable Gsus4/C/G shape. For example, a barre at the 5th fret will yield a C-C-C-F-C-F voicing, which functions as an Fsus4 chord or an F/C chord.
  • Power Chords: The three low G strings (6, 5, 4) naturally form a powerful low G octave/unison, perfect for heavy rhythmic playing or foundational drones. Simply fretting these three strings at any fret will give you a powerful root (e.g., 2nd fret for A, 3rd fret for Bb/A#).
  • Major/Minor Voicings: While not immediately apparent in the open tuning, simple two or three-finger shapes can unlock major and minor chords. For instance, to achieve a G Major sound, one might fret the 3rd and 1st strings down two semitones (at the 2nd fret) to B, creating G-G-G-B-G-B. The consistent G pedal makes it easy to imply G major or minor by adding the third (B or Bb) and fifth (D) on other strings.
• Drone & Percussion: The consistent G notes across three strings provide an excellent foundation for drone-based compositions and percussive techniques, where rhythmic articulation of the open strings can create a driving pulse.

Open String Notes:

• String 6 (Low E Equivalent): G2
• String 5 (A Equivalent): G2
• String 4 (D Equivalent): G2
• String 3 (G Equivalent): C4
• String 2 (B Equivalent): G3
• String 1 (High E Equivalent): C4

How to Tune (from Standard E Tuning):

Please exercise caution when tuning, especially with significant pitch changes. For movements exceeding 4 semitones (up or down), a different string gauge might be advisable to ensure string integrity and optimal tension.

• String 6 (E to G2): Tune up 3 semitones. This brings your string from E2 to G2.
• String 5 (A to G2): Tune down 2 semitones. This brings your string from A2 to G2.
• String 4 (D to G2): Tune down 7 semitones. This brings your string from D3 to G2. Caution: Tuning down 7 semitones is a significant change. Consider using a heavier gauge string for this.
• String 3 (G to C4): Tune up 5 semitones. This brings your string from G3 to C4. Caution: Tuning up 5 semitones is a significant change. Consider using a lighter gauge string to prevent breakage.
• String 2 (B to G3): Tune down 4 semitones. This brings your string from B3 to G3. Caution: Tuning down 4 semitones is at the upper limit for standard gauges; proceed carefully to maintain good intonation and feel.
• String 1 (High E to C4): Tune down 4 semitones. This brings your string from E4 to C4. Caution: Tuning down 4 semitones is at the upper limit for standard gauges; proceed carefully to maintain good intonation and feel.