Major seventh the same number of staff positions, but consist of a different number of semitones (nine and twelve). The easiest way to locate and identify the major seventh is from the octave rather than the unison, and it is suggested that one sings the octave first. For example, the most commonly cited example of a melody featuring a major seventh is the tonic-octave-major seventh of the opening to "(Somewhere) Over the Rainbow". "Not many songwriters begin a melody with a major seventh interval; perhaps that's why there are few memorable examples." However, two songs provide exceptions to this generalisation: Cole Porter's
Regular tuning intervals of minor sixths (eight semitones) and of major sixths (nine semitones), have received scholarly discussion. The chord charts for minor-sixths tuning are useful for left-handed guitarists playing in major-thirds tuning; the chord charts for major-sixths tuning, for left-handed guitarists playing in minor-thirds tuning. The regular tunings with minor-seventh (ten semitones) or major-seventh (eleven semitones) intervals would make conventional major/minor chord-playing very difficult, as would octave intervals. There are regular-tunings that have as their intervals either zero semi-tones (unison), one semi-tone (minor second), or two semi-tones (major second). These tunings tend to increase the difficulty in playing the major/minor system