Elision is a dramatic technique that places some of the action of a play off stage and away from the audience's eyes. Shakespeare first uses elision in the play Macbeth in the scene when Duncan's murder occurs. The playwright shows all of the events leading up to the brutal murder, like Macbeth and Lady Macbeth's debates over their wicked plan, but the actual murder occurs off stage. The audience then learns of the unseen action through Macbeth and Lady Macbeth's descriptions of what happened in Duncan's bedchamber.
Shakespeare uses this technique for two main reasons: using elision with Duncan's murder keeps the violent murder scene off stage, while maintaining focus on the true objective of the play, Macbeth's moral decline. In Shakespeare's day, portraying a bloody murder on stage would have been unpractical and not very realistic; by pretending that the murder has happened off-stage, Shakespeare does not have to rely on shoddy special effects to get his point across, but instead can use his best skill--the power of his words to create believable imagery--to challenge his audience's imaginations.