<P> In theatre, blocking is the precise staging of actors in order to facilitate the performance of a play, ballet, film or opera . Historically, the expectations of staging / blocking have changed substantially over time in Western theater . Prior to the movements towards "realism" that occurred in the 19th century, most staging used a "tableau" approach, in which a stage picture was established whenever characters entered or left the stage, ensuring that leading performers were always shown to their best advantage . In more recent times--while nothing has changed about showing leading performers to best advantage--there have been changing cultural expectations that have made blocking / staging more complicated . There are also artistic reasons why blocking can be crucial . Through careful use of positioning on the stage, a director or performer can establish or change the significance of a scene . Different artistic principles can inform blocking, including minimalism and naturalism . </P> <P> Both "blocking" and "block" were applied to stage and theater from as early as 1961 . The term derives from the practice of 19th - century theatre directors such as Sir W.S. Gilbert who worked out the staging of a scene on a miniature stage using blocks to represent each of the actors . (Gilbert's practice is depicted in Mike Leigh's 1999 film Topsy - Turvy .) </P> <P> In contemporary theater, the director usually determines blocking during rehearsal, telling actors where they should move for the proper dramatic effect, ensure sight lines for the audience and work with the lighting design of the scene . </P> <P> Each scene in a play is usually "blocked" as a unit, after which the director will move on to the next scene . The positioning of actors on stage in one scene will usually affect the possibilities for subsequent positioning unless the stage is cleared between scenes . </P>

Who makes the final decision on the blocking of the actors