Kanban is a lean manufacturing system that uses visual signals to trigger production. It originated at Toyota to maintain steady production levels based on actual customer demand. Kanban uses cards or other visual signals to trigger the replenishment or production of parts as they are needed. The system aims to reduce waste from overproduction by only producing what is needed when it is needed based on customer demand signals. Implementing kanban requires calculating the optimal number of signals and monitoring the system to ensure it functions as intended. Many manufacturers now use electronic kanban systems for improved visibility and integration with other systems.