The Citizen Eco Drive 8700 watch's movement "calibre" number is E870, which is the internal code the manufacturer uses to refer to the watch. The Eco Drive records the time and date, including the day of the week. If you've noticed the date on the watch is incorrect, set it using the recommended method. The date setting process takes fewer than five minutes in most cases.

Inspect the right side of the Citizen Eco Drive watch to get familiar with the controls. The button on the top-right edge is known as button "A." The knob beneath it is the crown. The button beneath the crown is known as button "B."

Pull the crown out one click to enter "Mode Setting." Turn it forward until the mode hand on the clock is pointed toward the calendar.

Pull the crown out one more click. This is the mode used to set the calendar.

Turn the crown forward or backward to set the year. Push "A" when the year is correct.

Turn the crown forward to set the month. Turning it backward will not adjust the month. Push "A" when it's correct. Turn the crown forward or backward to set the day of the month. Push "A."

Turn the crown forward or backward to set the day of the week. Push "A" when you are finished and push the crown back into its normal position.