Major thirds tuning string sets for standard tuning. Major-thirds tunings require less hand-stretching than other tunings, because each M3 tuning packs the octave's twelve notes into four consecutive frets. The major-third intervals allow major chords and minor chords to be played with two–three consecutive fingers on two consecutive frets. Every major-thirds tuning is regular and repetitive, two properties that facilitate learning by beginners and improvisation by advanced guitarists. In major-thirds tuning, the chromatic scale is arranged on three consecutive strings in four consecutive frets. This four-fret arrangement facilitates the left-hand technique for classical (Spanish) guitar: For each hand position of four frets, the
Rule of thirds (diving) Rule of thirds (diving) In scuba diving, the rule of thirds is a rule of thumb used by divers to plan dives so they have enough breathing gas remaining in their diving cylinder at the end of the dive to be able to complete the dive safely. This rule generally only applies to diving in overhead environments, such as caves and wrecks, where a direct ascent to the surface is impossible and the divers must return the way they came. For divers following the rule, one third of the gas supply is planned for the outward journey, one third is