The Japanese pull system using cards to signal production is kanban.
Kanban means “signboard” or “billboard” in Japanese. The method was developed at Toyota, where industrial engineer Taiichi Ohno adapted the visual replenishment logic of supermarkets to factory production. Instead of making parts simply because a schedule forecast says they may be needed, a downstream process requests replenishment after consuming stock.
A kanban card acts as a production or movement authorization. Its return can tell an upstream workstation to make a fixed quantity or transport a full container. Limiting the number of cards also limits work-in-progress and exposes bottlenecks, excess inventory, and process problems.
Kanban is often confused with JIT, but they are not identical: just-in-time is the broader production philosophy, while kanban is one signaling and control method used to support it. Heijunka means production leveling, and Kaizen means continuous improvement. Modern factories may replace physical cards with barcodes or electronic messages, but the pull principle remains the same.