‍Andon is the Japanese word for "lamp" and refers to a visual management system that makes the status of a production process visible at a glance. A key feature is not only the detection of a deviation, but also the immediate triggering of a response—from operator to team leader or from machine to system.

An Andon provides information on a variety of situations: production status (which machines are active), deviations (such as downtime, quality issues, processing errors, or material shortages), and necessary actions such as changeovers. The ratio of planned to actual output can also be displayed via an Andon.

A classic version is an illuminated panel with numbers corresponding to workstations or machines. As soon as a problem is detected by a sensor or because an operator pulls a cord or presses a button, the corresponding number lights up. This signal requires an immediate response from the team leader. Another common form is colored lights on top of machines: red for a problem, green for normal operation.

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The andon is closely linked to the principle of jidoka: by immediately highlighting problems and halting the line if necessary, it prevents errors from propagating further down the line.