A type of visual control that displays the current state of work (i.e., abnormal conditions, work instructions, and job progress information). It is one of the main tools of Jidoka. Often in the form of an electrical board which lights up to show at a glance the current state of work operations. Andon boards allow speedy corrective action to be taken by supervisors when a problem arises. Besides indicating abnormal situations, some Andons provide work instructions (such as quality checks, change of cutting tools and conveyance of parts) and job progress information.