Toyota has formulated six rules for the application of kanban
- Each process issues requests (kanban) to its suppliers as it consumes its supplies.
- Each process produces according to the quantity and sequence of incoming requests.
- No items are made or transported without a request.
- The request associated with an item is always attached to it.
- Processes must not send out defective items, to ensure that finished products will be defect-free.
- Limiting the number of pending requests makes the process more sensitive and reveals inefficiencies.