Nico. Regular tunings In standard tuning, there is an interval of a major third between the second and third strings, and all the other intervals are fourths. The irregularity has a price. Chords cannot be shifted around the fretboard in the standard tuning E–A–D–G–B–E, which requires four chord-shapes for the major chords. There are separate chord-forms for chords having their root note on the third, fourth, fifth, and sixth strings. These are called inversions. In contrast, regular tunings have equal intervals between the strings, and so they have symmetrical scales all along the fretboard. This makes it simpler to translate chords. For the regular tunings, chords may be moved diagonally around the fretboard. The diagonal movement of chords is especially simple for the regular tunings that are repetitive, in which case chords can be moved vertically: Chords can be moved three strings up (or down) in major-thirds tuning, and chords can be moved two strings up (or down) in augmented-fourths tuning. Regular tunings thus appeal to new guitarists and also to jazz-guitarists, whose improvisation is simplified by regular intervals. On the other hand, five- and six-string open chords ("cowboy chords") are more difficult to play in a regular tuning than in standard tuning. Instructional literature uses standard tuning. Traditionally a course begins with the hand in first position, that is, with the left-hand covering frets 1–4. Beginning players first learn open chords belonging to the major keys C, G, and D. Guitarists who play mainly open chords in these three major-keys and their relative minor-keys (Am, Em, Bm) may prefer standard tuning over many regular tunings, On the other hand, minor-thirds tuning features many barre chords with repeated notes, properties that appeal to acoustic-guitarists and beginners. Major thirds and perfect fourths Standard tuning mixes a major third (M3) with its perfect fourths. Regular tunings that are based on either major thirds or perfect fourths are used, for example, in jazz. All fourths tuning E2–A2–D3–G3–C4–F4 keeps the lowest four strings of standard tuning, changing the major third to a perfect fourth. Jazz musician Stanley Jordan stated that all-fourths tuning "simplifies the fingerboard, making it logical". Major-thirds tuning (M3 tuning) is a regular tuning in which the musical intervals between successive strings are each major thirds, for example E2–G2–C3–E3–G3–C4. Unlike all-fourths and all-fifths tuning, M3 tuning repeats its octave after three strings, which simplifies the learning of chords and improvisation. This repetition