The fingers are conventionally numbered 1 (index) through 4 (little finger) in music notation, such as sheet music and etude books. Especially in instructional editions of violin music, numbers over the notes may indicate which finger to use, with 0 or O indicating an open string. The chart to the right shows the arrangement of notes reachable in first position. Not shown on this chart is the way the spacing between note positions becomes closer as the fingers move up (in pitch) from the nut. The bars at the sides of the chart represent the usual possibilities for beginners' tape placements, at 1st, high 2nd, 3rd, and 4th fingers. Positions The placement of the left hand on the fingerboard is characterized by "positions". First position, where most beginners start (although some methods start in third position), is the most commonly used position in string music. Music composed for beginning youth orchestras is often mostly in first position. The lowest note available in this position in standard tuning is an open G3; the highest note in first position is played with the fourth finger on the E-string, sounding a B5. Moving the hand up the neck, the first finger takes the place of the second finger, bringing the player into second position. Letting the first finger take the first-position place of the third finger brings the player to third position, and so on. A change of positions, with its associated movement of the hand, is referred to as a shift, and effective shifting maintaining accurate intonation and a smooth legato (connected) sound is a key element of technique at all levels. Often a "guide finger" is used; the last finger to play a note in the old position continuously lightly touches the string during the course of the shift to end up on its correct place in the new position. In elementary shifting exercises the "guide finger" is often voiced while gliding up or down the string, so the player can establish correct placement by ear. Outside of these exercises it should rarely be audible (unless the performer is consciously applying a portamento effect for expressive reasons). In the course of a shift in low positions, the thumb of the left hand moves up or down the neck of the instrument so as to remain in the same position relative to the fingers (though the movement of the thumb may occur