The functions of the left and right hands





The primary function of the right hand is to beat time, while the role of the left hand is to portray or highlight in some way the expressive qualities of the music. [There is considerable debate about whether left-handed conductors should be permitted to reverse this distinction.]

One hand should not habitually imitate the other.
These two functions are not mutually exclusive, however.  The right hand, for example, can indicate dynamics (by varying the size of the beat) and musical style (by varying the shape and weight of the beat).  Similarly, the left hand may sometimes be employed to help performers deal with an accent, an accelerando or the beginning or ending of a phrase.   Even so, it is important to keep the functions of the two hands separated as much as possible.  A situation in which one hand habitually duplicates the actions of the other negates this distinction and both the conductor and the ensemble will be the poorer because of it.