Kanban is a lean production system that uses visual cards to signal the need for replenishment between processes. There are two main types of Kanban cards: withdrawal Kanban which authorize movement of parts between stages, and production Kanban which release orders to preceding stages. Other types include express, emergency, and through Kanbans. The number of Kanban cards needed is calculated based on demand, lead time, safety stock, and container size to balance production and inventory levels. Benefits of Kanban include reduced inventory and waste, increased flexibility and output, and lower total costs.