The Citizen 0840 is a mechanical watch movement that was introduced between 1968 and 1970. It is notable for being the first calibre to feature an electronically controlled balance motor. The movement includes several functions such as sweep seconds, a date function that can be set by changing the time between 23-24 hours, and a hack feature. The Citizen 0840 is an electronic movement with a sweep seconds hand and was used during the period of 1968-1970.