The physical movements and positioning of characters within a scene - where they stand, sit, walk, and orient themselves in space.
Blocking is the choreography of your characters' bodies in space. Borrowed from theater and film, it refers to how characters move through a scene - where they're standing relative to each other, how they cross a room, when they sit or rise, what they're physically doing while speaking or thinking. In fiction, good blocking gives readers a spatial map of the scene and uses physical positioning to reinforce emotional dynamics.
Without blocking, your scenes happen in a void. Characters become floating voices and disembodied thoughts. But blocking does more than just orient the reader spatially. A character who crosses to the far side of the room during an argument is telling you something. A character who sits when everyone else stands is telling you something. Physical positioning is a storytelling tool, not just a stage direction.
McCarthy's scenes are meticulously blocked - you always know exactly where Chigurh is standing relative to his victims, and that physical precision creates unbearable tension.
Austen uses ballroom positioning, drawing room seating arrangements, and walking paths to physically choreograph social dynamics and attraction between characters.
The blocking of Gatsby's parties - who stands where, who watches from across the room, who disappears upstairs - mirrors the social hierarchies and longing at the heart of the novel.
If a character was sitting at the start of a scene, they can't suddenly be at the window without getting up. Track your characters' positions and move them intentionally.
Don't establish positions in paragraph one and then let characters become stationary for five pages. People move, shift, fidget. Refresh blocking periodically.
You don't need to narrate every step. "She crossed to the window" works. You don't need "She stood up from the chair, turned to her left, walked four steps across the hardwood floor, and arrived at the window."
If your scene is set in a small apartment, characters can't be "across the vast room" from each other. Know your space and block within it realistically.
Pick a two-character dialogue scene from your work. Sketch a quick floor plan of the room on paper. Mark where each character starts. Now rewrite the scene, moving each character at least twice in ways that reflect the emotional arc of the conversation. If they start close and the conversation goes badly, move them apart. If they start distant and find connection, bring them together. Read the original and the revised version back to back.