Shifting is an important violin technique. In fact, shifting is an important technique for other string instruments as well like the cello and viola. The actual act of shifting is simple. The player is merely the moving his hand from one place on the fingerboard to another. Doing so well allows a player to maintain intonation while shifting to a higher or lower position. It also means that a player does not make the shift unnecessarily obvious. In order to accomplish smooth shifting, exercises are needed.
A simple shifting exercise involves placing the finger on the string and moving the finger, while still on the string to the new position. For instance, to shift from first finger B on the A string (first position) to first finger D on the A string (third position), the player needs to place his index finger on B then move to D while maintaining contact with the string. This may be done repeatedly until the player is comfortable with the shift. Then the shift can be incorporated into the piece or exercise that one is playing. Make certain that the shift is not completely obvious. It should not be audibly apparent that you are shifting, although it will be clear visually that shifting is being done. In music written during the Romantic period, however, the rule about not hearing a shift was relaxed, so that a violinist could shift positions while keeping the finger on the string long enough so that it was clear a shift was being made. This was meant to create a certain effect.
There are times when one needs to shift using more than one note. For instance, the solo violin part in the piece "Meditation" from the opera "Thais," by Jules Massenet, the A flat (on the E string) in the piu appassionato section of the piece, is followed by an F natural. Of course, these notes could be played on the A string, but for more advanced players or to create a certain effect, a shift in position may be desired. For instance, the A flat may be played on the E string and the F natural played on the A string. To prepare for this shift, a player can practice playing first finger A flat ( in thrid position) on the E string then first finger D flat on the A string (still in third position) and then shifting up to the F natural on the A string (in fifth position). The order of notes can then be reversed (F natural to get back to A flat). Repeat this pattern several times for the shift to become natural. Then when ready play the music with the shift being inaudible.
Various books have been written on shifting technique. One such book is by Yost System for violin by Gaylord Yost, which is unfortunately out of print, and Introducing the Positions Vol. I and II by Harvey S. Whistler.
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