Major-thirds tuning

Major thirds
Each major-thirds tuning packs the octave's 12 notes into 3 strings' 4 frets.
Basic information
Aliases	All-thirds (M3) tuning Augmented tuning
Interval	Major third
Semitones	4
Example(s)	G♯-C-E-G♯-C-E
Advanced information
Repetition	After 3 strings
Advantages	Octave on 4 frets, Major–minor chords on 2
Disadvantages	Reduced range on 6 strings
Left-handed tuning	Minor-sixths tuning
Ralph Patt popularized major-thirds tuning.
Regular tunings (semitones)
Trivial (0)
Minor thirds (3)
Major thirds (4)
All fourths (5)
Augmented fourths (6)
New standard (7, 3)
All fifths (7)
Minor sixths (8)
Guitar tunings

Among alternative tunings for guitar, a major-thirds tuning is a regular tuning in which each interval between successive open strings is a major third ("M3" in musical abbreviation). Other names for major-thirds tuning include major-third tuning, M3 tuning, all-thirds tuning, and augmented tuning. By definition, a major-third interval separates two notes that differ by exactly four semitones (one-third of the twelve-note octave).

The Spanish guitar's tuning mixes four perfect fourths (five semitones) and one major-third, the latter occurring between the G and B strings:

This tuning, which is used for acoustic and electric guitars, is called "standard" in English, a convention that is followed in this article. While standard tuning is irregular, mixing four fourths and one major third, M3 tunings are regular: Only major-third intervals occur between the successive strings of the M3 tunings, for example, the open augmented C tuning

For each M3 tuning, the open strings form an augmented triad in two octaves.

For guitars with six strings, every major-third tuning repeats its three open-notes in two octaves, so providing many options for fingering chords. By repeating open-string notes and by having uniform intervals between strings, major-thirds tuning simplifies learning by beginners. These features also facilitate advanced guitarists' improvisation, precisely the aim of jazz guitarist Ralph Patt when he began popularizing major-thirds tuning between 1963 and 1964.