Though it may appear that the left hand on the neck of the violin is holding the instrument in place, the primary support is the left side of the jaw pressing down on the chinrest and holding the violin against the left shoulder. A shoulder rest or elastic straps might be used to seat the violin properly against the shoulder. The bow is held in the right hand with the thumb pressed into the gap between the heel of the stick and the winding of the horsehair that fastens the strand to the stick — the other fingers are wrapped widely, but firmly, around the stick.
The strings of the violin release their sound in several ways, from the action of the bow being pulled over them, called arco, from plucking them with fingers, called pizzicato, or from striking the strings with the bow, called col legno. The violin will produce a louder note by either increasing the speed of the bow movement or increasing the pressure of the bow on the strings. The right arm’s control of the bow influences the rhythm and tone quality of the music produced, as well as the articulation of the notes.
The left hand controls the pitch of the notes by pressing a string against the fingerboard with a finger, also called ‘stopping’ the string. A violin fingerboard has no frets, so a violinist must learn not only where the fingers must be placed on the fingerboard to produce a note of the correct pitch, but also must remember that unmarked location each time.
One way a violinist can keep track of correct fingering is the use of relative positioning — each finger moves to the place of its neighbor. The first position is the lowest position one full-note step down the fingerboard from the scroll. Kinesthetic and aural feedback guide the violinists in the placement of the fingers — in other words, good violinists do not look at their fingers, but rather hear and feel the sound that is created at each positioning of the fingers.
A violinist must then select which string to press down and which finger to use to create a note via a stroke of the bow. Then, to produce a new note, the hand and the fingers must move to a new placement on the fingerboard — this action is called shifting. An unpressured guide finger is used to move the entire hand accurately along the strings to a new position. The highest possible position is the 15th, though the practical highest position for most violinists is the 7th.
The bow can also play an open string, one that is not held down by a finger, alone or in combination with other held strings. One of the earliest learning milestone for a beginner is to play the ringing tones, where the sound created by bowing a held string causes a sympathetic resonance in an open string. In the first position, nine such notes exist.
Use of the bow is just as complicated. Speed of movement and downward pressure can both be varied; the location along the string where the the bow contacts the string is also a choice. The touch of the bow to the string can be described as bouncing, glued, hammered, shuffled, chopped or many other evocative terms, often via the original French, German or Italian words.