Production triggered by actual downstream demand rather than upstream forecasts or schedules. In push production (the mass-production default), a central plan schedules production at each station, pushing materials forward regardless of downstream need. In pull production, work begins only when a downstream process signals need — typically via kanban. taiichi-ohno's insight came from the American supermarket: shelf space is replenished only when customers pull items from it. No demand, no production. Pull systems naturally limit work-in-progress, prevent overproduction (the worst of the seven wastes), and make actual demand visible throughout the system. The pull principle is TPS's most broadly applicable concept — it appears in Kanban for knowledge work (WIP limits), in DevOps (deployment triggered by readiness, not schedule), and in Agile (pulling stories from a backlog rather than assigning work to teams).