Major thirds tuning hand is stationary and the fingers move, each finger being responsible for one fret. Consequently, three hand-positions (covering frets 1–4, 5–8, and 9–12) partition the fingerboard of classical guitar, which has exactly 12 frets. Only two or three frets are needed for the guitar chords—major, minor, and dominant sevenths—which are emphasized in introductions to guitar-playing and to the fundamentals of music. Each major and minor chord can be played on two successive frets on three successive strings, and therefore each needs only two fingers. Other chords—seconds, fourths, sevenths, and ninths—are played on only three successive frets. For fundamental-chord fingerings, major-thirds
Four Thirds system Thirds cameras came to an end after the introduction of the mirrorless Micro Four Thirds format. Discontinued models include: The Four Thirds lens mount is specified to be a bayonet type with a flange focal distance of 38.67 mm. There are currently around three dozen lenses for the Four Thirds System standard. Before announcing that it would stop production of Four Thirds lenses in early 2017, Olympus produced about 20 lenses for the Four Thirds System under their "Zuiko Digital" brand. They are divided into three grades — Standard, High Grade and Super High Grade. High Grade lenses have faster