Citizen quartz watches are manufactured by Tokyo-based Citizen Holdings Co., Ltd. Hundreds of models have been produced featuring the month/date/day, date/day and day only functions. In 2009, more than 150 Citizen quartz watches were manufactured with these features. Setting the day depends on whether the watch is an analog or digital, or an analog/digital combination. Each new Citizen quartz watch is accompanied by an operator’s manual. Replacement manuals can be found online and at an authorized Citizen watch dealer.

To set the day of a Citizen quartz watch, the caliber movement must be identified. The caliber and case numbers are located on the case back of the watch. It’s the first three or four digits on the fourth line. It may be four numbers, a single letter and three numbers, or simply three numbers. A specific operator’s manual with complete month/day/date setting details have been issued for each caliber.

All Citizen analog quartz watches that feature a date and day aperture can be set in the same manner. Pull the crown at 3 o’clock to the first position. The date can be set on the caliber E000 Eco-Drive, for example, by rotating the crown counterclockwise to set the date. Rotate the crown clockwise to set the day of the week. Push the crown flush against the case when the date and day are set.

Most Citizen analog watches are sensitive to when the day is set. Watches can’t tell whether it’s daytime or evening unless you set the calendar functions properly. If setting the date and day functions between 9 p.m. and 1 a.m. on a caliber 0580 Chronograph, for example, the watch may not change over to the new date and day after midnight and will require re-setting in the morning.

Some Citizen quartz watches have multiple function buttons to set the date and day. The caliber 0870 Chronograph has three buttons on the right side at the 2, 3 and 4 o’clock positions. Press the 4 o’clock button to set the calendar mode, and then pull the same button out. Then press the 2 o’clock button to change the date. Continue pressing the 2 o’clock button until the correct month and date are displayed.

Digital models are more complicated to set the day than analog watches, primarily because the calendar mode must be set first with one button, and then the day set with another button. Press the 3 o’clock button on digital quartz models, such as the caliber B080 version and similar models, to display the calendar/temperature mode. Continuously press the button for more than two seconds and the date will flash. Continue pressing until the correct date appears.