Major thirds tuning also facilitate advanced guitarists' improvisation, precisely the aim of jazz guitarist Ralph Patt when he began popularizing major-thirds tuning between 1963 and 1964. In standard tuning, the successive open-strings mix two types of intervals, four perfect-fourths and the major third between the G and B strings: Only major thirds occur as open-string intervals for major-thirds tuning, which is also called ""major-third" tuning", ""all-thirds" tuning", and ""M3" tuning". A popular M3 tuning has the open strings in which the low G is a major third above the low E of standard tuning. Consequently, a seventh string for the low E is
Major thirds tuning improvisation. In contrast, chords cannot be shifted around the fretboard in standard tuning, which requires four chord-shapes for the major chords: There are separate fingerings for chords having root notes on one of the four strings three–six. The repetition of the major-thirds tuning enables notes and chords to be raised one octave by being "vertically" shifted by three strings. Notes and chords may be shifted "diagonally" in major-thirds tuning, by combining a vertical shift of one string with a horizontal shift of four frets: "Like all regular tunings, chords in the major third tuning can be moved across the fretboard