Open C tuning is a powerful and resonant setup for the guitar. It is based around the three notes that form the triad of a C major chord: C, the root note; G, the perfect fifth; and E, the major third. This creates a full C major chord when all open strings are strummed, offering a rich and harmonic foundation. This tuning has been famously used by Justin Hayward (Moody Blues) on his acoustic guitar for 'Question' (from the 'Question of Balance' LP) and is also extensively featured in the work of John Butler.

Technical Analysis:

• The open string configuration (C2-G2-C3-G3-C4-E4) immediately forms a C major chord, providing a deeply resonant and harmonically complete sound.
• The arrangement of the strings with repeating C and G notes, particularly the octaves and perfect fifths, allows for easy creation of drone-like textures and gives the tuning a naturally 'open' feel.
• A significant advantage of Open C is that barring across any single fret will produce a major chord. For example, barring all strings at the 1st fret will yield a C# major chord, the 2nd fret a D major chord, and so on, simplifying major chord progressions.
• Beyond simple barre chords, the unique intervals open up new melodic and harmonic possibilities, encouraging players to explore voicings and arpeggios that are distinct from standard tuning.
• The substantial down-tuning on the lower strings (especially the 6th string to C2) contributes to a deep, full bass response, while the presence of the high E (string 1) adds brightness and sparkle.

Target Notes:

• String 6: C2
• String 5: G2
• String 4: C3
• String 3: G3
• String 2: C4
• String 1: E4

How to Tune:

• String 6 (Low E): Tune down 4 semitones from E to C. This is a significant change, and for optimal string tension and longevity, considering a heavier gauge string might be beneficial for this string.
• String 5 (A): Tune down 2 semitones from A to G.
• String 4 (D): Tune down 2 semitones from D to C.
• String 3 (G): Keep as is; no change (0 semitones).
• String 2 (B): Tune up 1 semitone from B to C.
• String 1 (High E): Keep as is; no change (0 semitones).