This unique guitar tuning, known as "Isato Nakagawa - Tohobijin", is notably utilized by the esteemed fingerstyle guitarist Isato Nakagawa in his composition "Tohobijin". It presents a deeply resonant and harmonically rich soundscape, building upon a strong G major foundation with a distinctive major seventh quality.

The open string notes are G1, B1, D3, F#3, B3, D4. This arrangement inherently creates an Open G Major 7th chord (G-B-D-F#-B-D) when strummed open, offering immediate access to a bright, yet complex, harmonic texture. The lowest three strings (G1, B1, D3) form a clear G Major triad, providing a powerful bass foundation. The upper strings (F#3, B3, D4), while not a standard G chord inversion on their own, beautifully complete the Gmaj7 chord when combined with the lower notes, adding sparkle and intricate voicings.

Technically, the tuning moves significantly away from standard EADGBe. The deepest strings, G1 and B1, are tuned down 9 and 10 semitones respectively from their standard E2 and A2 positions. Such extreme detuning necessitates careful consideration of string gauge; as the original description advises, heavier gauge strings for the low G and B are highly recommended to maintain proper tension and intonation, and to prevent string breakage or buzzing. This tuning excels in fingerstyle arrangements, allowing for lush harmonic interplay and easily accessible open-chord voicings that would be challenging in standard tuning.

Potential chords and voicings that become readily available include:

• Open G Major 7th: Strumming all open strings directly yields a vibrant Gmaj7 chord.
• Barre Chords: By simply barring across any fret, you can easily create major 7th chords in the corresponding key (e.g., barring at the 1st fret creates a G#maj7, 2nd fret an Amaj7, etc.).
• Root-Fifth Bass Lines: The G-B-D on the lower strings allows for easy construction of powerful major triad bass lines.
• Melodic Opportunities: The inherent Gmaj7 structure provides a rich harmonic bed for melodic development, particularly in keys related to G major.

How to Tune to Isato Nakagawa - Tohobijin (G B D F# B D)

To achieve this unique tuning, follow these specific adjustments from standard EADGBe tuning. Please note the significant drops on the lowest strings, which may require heavier gauge strings for optimal performance and to avoid string breakage or buzzing.

• 6th String (Low E): From standard E2, tune down 9 semitones to G1. (Movement: -9 semitones)
• 5th String (A): From standard A2, tune down 10 semitones to B1. (Movement: -10 semitones)
• 4th String (D): Keep as is; no change (0 semitones) from D3. (Movement: 0 semitones)
• 3rd String (G): From standard G3, tune down 1 semitone to F#3. (Movement: -1 semitone)
• 2nd String (B): Keep as is; no change (0 semitones) from B3. (Movement: 0 semitones)
• 1st String (High E): From standard E4, tune down 2 semitones to D4. (Movement: -2 semitones)