One of the principal tasks of the concertmaster is to provide bowings for the 1st violins prior to rehearsal. This entails a great knowledge of historical playing styles in addition to complete idiomatic understanding of the mechanics of string playing. Section leaders among the other strings will base their bowings on those of the concertmaster and these section leaders (called principals) may confer during rehearsal in order to ensure unity and cohesion of execution between the string sections. Ensemble cohesion emanates directly from the contact and connection between these vital front desk positions. The concertmaster assumes responsibility for the tone and execution of the entire section of 1st violins, in addition to performing any solo passages that occur in a given piece.