Getting acquainted with the mandolin fretboard is no easy trick, and requires years of practice and study. Beginners usually start out playing only on the first few frets, using only the first two or three fingers of the left hand. Nevertheless, good technique demands the use of all the fingers, and most (if not all) of the fretboard.
The mandolin fretboard, like the violin fingerboard, is divided into (at least) six fingering positions, which are determined by the placement of the left hand. In the first, or open position, the first finger covers the 1st and 2nd frets, the second finger covers the 3rd and 4th frets, the third finger covers the 5th and 6th frets, and the fourth finger covers the 7th and 8th frets. The second position is arrived at by moving the first finger up to the area previously covered by the second finger (in the first position). The third position is reached by moving the first finger up to the area previously covered by the third finger, and so on up the fretboard, as shown in the examples below.
By utilizing the different positions, higher and more difficult passages may be played more easily and comfortably. Most mandolin (and violin) music indicates any position shifts with fingering numbers printed above the notes in question.
In general, it is best to make as few position shifts as possible. Tone production is significantly more difficult in the higher positions, and playing in those positions is more difficult, especially on lower-quality instruments. The first position, being the most brilliant-sounding of all, deserves to be given preference. An old orchestral rule says: "Stay in the first position as long as you can!"
To acquaint yourself with the various positions, practice the major scales written below. Each scale encompasses two octaves, a range that may be comfortably attained within any one position. Notice that the same scale (or musical passage) may be played in more than one position. Try playing different scales, tunes, and licks in each of the positions until you get acquainted with them. In practicing the various positions, avoid the use of open strings as much as possible. Keep your left hand close to the fretboard at all times, and try to leave your fingers on the previously fretted notes as long as possible.